Add Swagger doc filter for /api/auth proxy login endpoint

Introduced AuthProxyDocumentFilter to programmatically document the POST /api/auth proxy login endpoint in Swagger. The filter defines request body schemas, example values, query parameter, and response codes. Registered the filter in Program.cs for OpenAPI generation.

EnvelopeGenerator.API/Controllers/AnnotationController.cs

@@ -0,0 +1,118 @@
+using DigitalData.Core.Abstraction.Application.DTO;
+using DigitalData.Core.Exceptions;
+using EnvelopeGenerator.Application.Common.Extensions;
+using EnvelopeGenerator.Application.Common.Interfaces.Services;
+using EnvelopeGenerator.Application.Common.Notifications.DocSigned;
+using EnvelopeGenerator.Application.EnvelopeReceivers.Queries;
+using EnvelopeGenerator.Application.Histories.Queries;
+using EnvelopeGenerator.Domain.Constants;
+using EnvelopeGenerator.API.Extensions;
+using MediatR;
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.AspNetCore.Authentication.Cookies;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.API.Controllers;
+
+/// <summary>
+/// Manages annotations and signature lifecycle for envelopes.
+/// </summary>
+[Authorize(Roles = Role.Receiver.FullyAuth)]
+[ApiController]
+[Route("api/[controller]")]
+public class AnnotationController : ControllerBase
+{
+    [Obsolete("Use MediatR")]
+    private readonly IEnvelopeHistoryService _historyService;
+
+    [Obsolete("Use MediatR")]
+    private readonly IEnvelopeReceiverService _envelopeReceiverService;
+
+    private readonly IMediator _mediator;
+
+    private readonly ILogger<AnnotationController> _logger;
+
+    /// <summary>
+    /// Initializes a new instance of <see cref="AnnotationController"/>.
+    /// </summary>
+    [Obsolete("Use MediatR")]
+    public AnnotationController(
+        ILogger<AnnotationController> logger,
+        IEnvelopeHistoryService envelopeHistoryService,
+        IEnvelopeReceiverService envelopeReceiverService,
+        IMediator mediator)
+    {
+        _historyService = envelopeHistoryService;
+        _envelopeReceiverService = envelopeReceiverService;
+        _mediator = mediator;
+        _logger = logger;
+    }
+
+    /// <summary>
+    /// Creates or updates annotations for the authenticated envelope receiver.
+    /// </summary>
+    /// <param name="psPdfKitAnnotation">Annotation payload.</param>
+    /// <param name="cancel">Cancellation token.</param>
+    [Authorize(Roles = Role.Receiver.FullyAuth)]
+    [HttpPost]
+    [Obsolete("PSPDF Kit will no longer be used.")]
+    public async Task<IActionResult> CreateOrUpdate([FromBody] PsPdfKitAnnotation? psPdfKitAnnotation = null, CancellationToken cancel = default)
+    {
+        var signature = User.GetReceiverSignatureOfReceiver();
+        var uuid = User.GetEnvelopeUuidOfReceiver();
+
+        var envelopeReceiver = await _mediator.ReadEnvelopeReceiverAsync(uuid, signature, cancel).ThrowIfNull(Exceptions.NotFound);
+
+        if (!envelopeReceiver.Envelope!.ReadOnly && psPdfKitAnnotation is null)
+            return BadRequest();
+
+        if (await _mediator.IsSignedAsync(uuid, signature, cancel))
+            return Problem(statusCode: StatusCodes.Status409Conflict);
+        else if (await _mediator.AnyHistoryAsync(uuid, new[] { EnvelopeStatus.EnvelopeRejected, EnvelopeStatus.DocumentRejected }, cancel))
+            return Problem(statusCode: StatusCodes.Status423Locked);
+
+        var docSignedNotification = await _mediator
+            .ReadEnvelopeReceiverAsync(uuid, signature, cancel)
+            .ToDocSignedNotification(psPdfKitAnnotation)
+            ?? throw new NotFoundException("Envelope receiver is not found.");
+
+        await _mediator.PublishSafely(docSignedNotification, cancel);
+        await HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
+
+        return Ok();
+    }
+
+    /// <summary>
+    /// Rejects the document for the current receiver.
+    /// </summary>
+    /// <param name="reason">Optional rejection reason.</param>
+    [Authorize(Roles = Role.Receiver.FullyAuth)]
+    [HttpPost("reject")]
+    [Obsolete("Use MediatR")]
+    public async Task<IActionResult> Reject([FromBody] string? reason = null)
+    {
+        var signature = User.GetReceiverSignatureOfReceiver();
+        var uuid = User.GetEnvelopeUuidOfReceiver();
+        var mail = User.GetReceiverMailOfReceiver();
+
+        var envRcvRes = await _envelopeReceiverService.ReadByUuidSignatureAsync(uuid: uuid, signature: signature);
+
+        if (envRcvRes.IsFailed)
+        {
+            _logger.LogNotice(envRcvRes.Notices);
+            return Unauthorized("you are not authorized");
+        }
+
+        var histRes = await _historyService.RecordAsync(envRcvRes.Data.EnvelopeId, userReference: mail, EnvelopeStatus.DocumentRejected, comment: reason);
+        if (histRes.IsSuccess)
+        {
+            await HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
+            return NoContent();
+        }
+
+        _logger.LogEnvelopeError(uuid: uuid, signature: signature, message: "Unexpected error happened in api/envelope/reject");
+        _logger.LogNotice(histRes.Notices);
+        return StatusCode(500, histRes.Messages);
+    }
+}

EnvelopeGenerator.API/Controllers/AuthController.cs

@@ -0,0 +1,59 @@
+using Microsoft.AspNetCore.Authentication.Cookies;
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Authorization;
+using EnvelopeGenerator.API.Models;
+
+namespace EnvelopeGenerator.API.Controllers;
+
+/// <summary>
+/// Controller verantwortlich für die Benutzer-Authentifizierung, einschließlich Anmelden, Abmelden und Überprüfung des Authentifizierungsstatus.
+/// </summary>
+/// <param name="logger"></param>
+[Route("api/[controller]")]
+[ApiController]
+public partial class AuthController(ILogger<AuthController> logger) : ControllerBase
+{
+
+    /// <summary>
+    /// Entfernt das Authentifizierungs-Cookie des Benutzers (AuthCookie)
+    /// </summary>
+    /// <returns>
+    /// Gibt eine HTTP 200 oder 401.
+    /// </returns>
+    /// <remarks>
+    /// Sample request:
+    ///
+    ///     POST /api/auth/logout
+    ///
+    /// </remarks>
+    /// <response code="200">Erfolgreich gelöscht, wenn der Benutzer ein berechtigtes Cookie hat.</response>
+    /// <response code="401">Wenn es kein zugelassenes Cookie gibt, wird „nicht zugelassen“ zurückgegeben.</response>
+    [ProducesResponseType(typeof(string), StatusCodes.Status200OK, "text/javascript")]
+    [ProducesResponseType(typeof(void), StatusCodes.Status401Unauthorized)]
+    [Authorize]
+    [HttpPost("logout")]
+    public async Task<IActionResult> Logout()
+    {
+        await HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
+        return Ok();
+    }
+
+    /// <summary>
+    /// Prüft, ob der Benutzer ein autorisiertes Token hat.
+    /// </summary>
+    /// <returns>Wenn ein autorisiertes Token vorhanden ist HTTP 200 asynchron 401</returns>
+    /// <remarks>
+    /// Sample request:
+    ///
+    ///     GET /api/auth
+    ///
+    /// </remarks>
+    /// <response code="200">Wenn es einen autorisierten Cookie gibt.</response>
+    /// <response code="401">Wenn kein Cookie vorhanden ist oder nicht autorisierte.</response>
+    [ProducesResponseType(typeof(string), StatusCodes.Status200OK, "text/javascript")]
+    [ProducesResponseType(typeof(void), StatusCodes.Status401Unauthorized)]
+    [Authorize]
+    [HttpGet]
+    public IActionResult IsAuthenticated() => Ok();
+}

EnvelopeGenerator.API/Controllers/ConfigController.cs

@@ -0,0 +1,30 @@
+using EnvelopeGenerator.API.Models.PsPdfKitAnnotation;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Options;
+
+namespace EnvelopeGenerator.API.Controllers;
+
+/// <summary>
+/// Exposes configuration data required by the client applications.
+/// </summary>
+/// <remarks>
+/// Initializes a new instance of <see cref="ConfigController"/>.
+/// </remarks>
+[Route("api/[controller]")]
+[ApiController]
+[Authorize]
+public class ConfigController(IOptionsMonitor<AnnotationParams> annotationParamsOptions) : ControllerBase
+{
+    private readonly AnnotationParams _annotationParams = annotationParamsOptions.CurrentValue;
+
+    /// <summary>
+    /// Returns annotation configuration that was previously rendered by MVC.
+    /// </summary>
+    [HttpGet("Annotations")]
+    [Obsolete("PSPDF Kit will no longer be used.")]
+    public IActionResult GetAnnotationParams()
+    {
+        return Ok(_annotationParams.AnnotationJSObject);
+    }
+}

EnvelopeGenerator.API/Controllers/DocumentController.cs

@@ -0,0 +1,57 @@
+using EnvelopeGenerator.API.Extensions;
+using EnvelopeGenerator.Application.Documents.Queries;
+using EnvelopeGenerator.Domain.Constants;
+using MediatR;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.API.Controllers;
+
+/// <summary>
+/// Provides access to envelope documents for authenticated receivers.
+/// </summary>
+/// <remarks>
+/// Initializes a new instance of the <see cref="DocumentController"/> class.
+/// </remarks>
+[Authorize]
+[ApiController]
+[Route("api/[controller]")]
+public class DocumentController(IMediator mediator, ILogger<DocumentController> logger) : ControllerBase
+{
+    /// <summary>
+    /// Returns the document bytes receiver.
+    /// </summary>
+    /// <param name="query">Encoded envelope key.</param>
+    /// <param name="cancel">Cancellation token.</param>
+    [HttpGet]
+    [Authorize(Roles = $"{Role.Sender},{Role.Receiver.FullyAuth}")]
+    public async Task<IActionResult> GetDocument(CancellationToken cancel, [FromQuery] ReadDocumentQuery? query = null)
+    {
+        // Sender: expects query with envelope key
+        if (User.IsInRole(Role.Sender))
+        {
+            if (query is null)
+                return BadRequest("Missing document query.");
+
+            var senderDoc = await mediator.Send(query, cancel);
+            return senderDoc.ByteData is byte[] senderDocByte
+                ? File(senderDocByte, "application/octet-stream")
+                : NotFound("Document is empty.");
+        }
+
+        // Receiver: resolve envelope id from claims
+        if (User.IsInRole(Role.Receiver.FullyAuth))
+        {           
+            if (query is not null)
+                return BadRequest("Query parameters are not allowed for receiver role.");
+
+            var envelopeId = User.GetEnvelopeIdOfReceiver();
+            var receiverDoc = await mediator.Send(new ReadDocumentQuery { EnvelopeId = envelopeId }, cancel);
+            return receiverDoc.ByteData is byte[] receiverDocByte
+                ? File(receiverDocByte, "application/octet-stream")
+                : NotFound("Document is empty.");
+        }
+
+        return Unauthorized();
+    }
+}

EnvelopeGenerator.API/Controllers/EmailTemplateController.cs

@@ -5,14 +5,14 @@ using EnvelopeGenerator.Application.EmailTemplates.Commands.Reset;
 using EnvelopeGenerator.Application.EmailTemplates.Queries.Read;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
-using EnvelopeGenerator.Application.Contracts.Repositories;
-using EnvelopeGenerator.Application.DTOs;
 using MediatR;
 using System.Threading.Tasks;
-using DigitalData.UserManager.Application.Services;
-using EnvelopeGenerator.Application.Exceptions;
+using EnvelopeGenerator.Application.Common.Dto;
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+using Microsoft.EntityFrameworkCore;
 
-namespace EnvelopeGenerator.GeneratorAPI.Controllers;
+namespace EnvelopeGenerator.API.Controllers;
 
 /// <summary>
 /// Controller for managing temp templates.
@@ -23,11 +23,9 @@ namespace EnvelopeGenerator.GeneratorAPI.Controllers;
 [Authorize]
 public class EmailTemplateController : ControllerBase
 {
-    private readonly ILogger<EmailTemplateController> _logger;
-
     private readonly IMapper _mapper;
 
-    private readonly IEmailTemplateRepository _repository;
+    private readonly IRepository<EmailTemplate> _repository;
 
     private readonly IMediator _mediator;
 
@@ -38,11 +36,11 @@ public class EmailTemplateController : ControllerBase
     /// <param name="repository">
     /// Die AutoMapper-Instanz, die zum Zuordnen von Objekten verwendet wird.
     /// </param>
-    public EmailTemplateController(IMapper mapper, IEmailTemplateRepository repository, ILogger<EmailTemplateController> logger, IMediator mediator)
+    [Obsolete("Use MediatR")]
+    public EmailTemplateController(IMapper mapper, IRepository<EmailTemplate> repository, IMediator mediator)
     {
         _mapper = mapper;
         _repository = repository;
-        _logger = logger;
         _mediator = mediator;
     }
 
@@ -65,7 +63,7 @@ public class EmailTemplateController : ControllerBase
     {
         if (emailTemplate is null || (emailTemplate.Id is null && emailTemplate.Type is null))
         {
-            var temps = await _repository.ReadAllAsync();
+            var temps = await _repository.Query.ToListAsync();
             return Ok(_mapper.Map<IEnumerable<EmailTemplateDto>>(temps));
         }
         else

EnvelopeGenerator.API/Controllers/EnvelopeController.cs

@@ -0,0 +1,111 @@
+using EnvelopeGenerator.API.Extensions;
+using EnvelopeGenerator.Application.Envelopes.Commands;
+using EnvelopeGenerator.Application.Envelopes.Queries;
+using MediatR;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Newtonsoft.Json;
+
+namespace EnvelopeGenerator.API.Controllers;
+
+/// <summary>
+/// Dieser Controller stellt Endpunkte für die Verwaltung von Umschlägen bereit.
+/// </summary>
+/// <remarks>
+/// Die API ermöglicht das Abrufen und Verwalten von Umschlägen basierend auf Benutzerinformationen und Statusfiltern.
+/// 
+/// Mögliche Antworten:
+/// - 200 OK: Die Anfrage war erfolgreich, und die angeforderten Daten werden zurückgegeben.
+/// - 400 Bad Request: Die Anfrage war fehlerhaft oder unvollständig.
+/// - 401 Unauthorized: Der Benutzer ist nicht authentifiziert.
+/// - 403 Forbidden: Der Benutzer hat keine Berechtigung, auf die Ressource zuzugreifen.
+/// - 404 Not Found: Die angeforderte Ressource wurde nicht gefunden.
+/// - 500 Internal Server Error: Ein unerwarteter Fehler ist aufgetreten.
+/// </remarks>
+[Route("api/[controller]")]
+[ApiController]
+[Authorize]
+public class EnvelopeController : ControllerBase
+{
+    private readonly ILogger<EnvelopeController> _logger;
+    private readonly IMediator _mediator;
+
+    /// <summary>
+    /// Erstellt eine neue Instanz des EnvelopeControllers.
+    /// </summary>
+    /// <param name="logger">Der Logger, der für das Protokollieren von Informationen verwendet wird.</param>
+    /// <param name="mediator"></param>
+    public EnvelopeController(ILogger<EnvelopeController> logger, IMediator mediator)
+    {
+        _logger = logger;
+        _mediator = mediator;
+    }
+
+    /// <summary>
+    /// Ruft eine Liste von Umschlägen basierend auf dem Benutzer und den angegebenen Statusfiltern ab.
+    /// </summary>
+    /// <param name="envelope"></param>
+    /// <returns>Eine IActionResult-Instanz, die die abgerufenen Umschläge oder einen Fehlerstatus enthält.</returns>
+    /// <response code="200">Die Anfrage war erfolgreich, und die Umschläge werden zurückgegeben.</response>
+    /// <response code="400">Die Anfrage war fehlerhaft oder unvollständig.</response>
+    /// <response code="401">Der Benutzer ist nicht authentifiziert.</response>
+    /// <response code="403">Der Benutzer hat keine Berechtigung, auf die Ressource zuzugreifen.</response>
+    /// <response code="500">Ein unerwarteter Fehler ist aufgetreten.</response>
+    [Authorize]
+    [HttpGet]
+    public async Task<IActionResult> GetAsync([FromQuery] ReadEnvelopeQuery envelope)
+    {
+        var result = await _mediator.Send(envelope.Authorize(User.GetId()));
+        return result.Any() ? Ok(result) : NotFound();
+    }
+
+    /// <summary>
+    /// Ruft das Ergebnis eines Dokuments basierend auf der ID ab.
+    /// </summary>
+    /// <param name="query"></param>
+    /// <param name="view">Gibt an, ob das Dokument inline angezeigt werden soll (true) oder als Download bereitgestellt wird (false).</param>
+    /// <returns>Eine IActionResult-Instanz, die das Dokument oder einen Fehlerstatus enthält.</returns>
+    /// <response code="200">Das Dokument wurde erfolgreich abgerufen.</response>
+    /// <response code="404">Das Dokument wurde nicht gefunden oder ist nicht verfügbar.</response>
+    /// <response code="500">Ein unerwarteter Fehler ist aufgetreten.</response>
+    [HttpGet("doc-result")]
+    public async Task<IActionResult> GetDocResultAsync([FromQuery] ReadEnvelopeQuery query, [FromQuery] bool view = false)
+    {
+        var envelopes = await _mediator.Send(query.Authorize(User.GetId()));
+        var envelope = envelopes.FirstOrDefault();
+
+        if (envelope is null)
+            return NotFound("Envelope not available.");
+        if (envelope.DocResult is null)
+            return NotFound("The document has not been fully signed or the result has not yet been released.");
+
+        if (view)
+        {
+            Response.Headers.Append("Content-Disposition", "inline; filename=\"" + envelope.Uuid + ".pdf\"");
+            return File(envelope.DocResult, "application/pdf");
+        }
+
+        return File(envelope.DocResult, "application/pdf", $"{envelope.Uuid}.pdf");
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="command"></param>
+    /// <returns></returns>
+    [NonAction]
+    [Authorize]
+    [HttpPost]
+    public async Task<IActionResult> CreateAsync([FromBody] CreateEnvelopeCommand command)
+    {
+        var res = await _mediator.Send(command.Authorize(User.GetId()));
+
+        if (res is null)
+        {
+            _logger.LogError("Failed to create envelope. Envelope details: {EnvelopeDetails}", JsonConvert.SerializeObject(command));
+            return StatusCode(StatusCodes.Status500InternalServerError);
+        }
+        else
+            return Ok(res);
+    }
+}

EnvelopeGenerator.API/Controllers/EnvelopeReceiverController.cs

@@ -1,22 +1,21 @@
 using AutoMapper;
-using DigitalData.Core.DTO;
-using EnvelopeGenerator.Application.Contracts.Services;
-using EnvelopeGenerator.Application.Contracts.SQLExecutor;
-using EnvelopeGenerator.Application.DTOs.Receiver;
-using EnvelopeGenerator.Application.EnvelopeReceivers.Commands.Create;
-using EnvelopeGenerator.Application.EnvelopeReceivers.Queries.Read;
-using EnvelopeGenerator.Application.Envelopes.Queries.ReceiverName;
-using EnvelopeGenerator.Application.SQL;
+using EnvelopeGenerator.Application.EnvelopeReceivers.Commands;
+using EnvelopeGenerator.Application.EnvelopeReceivers.Queries;
+using EnvelopeGenerator.Application.Envelopes.Queries;
 using EnvelopeGenerator.Domain.Entities;
-using EnvelopeGenerator.GeneratorAPI.Models;
+using EnvelopeGenerator.API.Models;
 using MediatR;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Data.SqlClient;
 using Microsoft.Extensions.Options;
 using System.Data;
+using EnvelopeGenerator.Application.Common.SQL;
+using EnvelopeGenerator.Application.Common.Dto.Receiver;
+using EnvelopeGenerator.Application.Common.Interfaces.SQLExecutor;
+using EnvelopeGenerator.API.Extensions;
 
-namespace EnvelopeGenerator.GeneratorAPI.Controllers;
+namespace EnvelopeGenerator.API.Controllers;
 
 /// <summary>
 /// Controller für die Verwaltung von Umschlagempfängern.
@@ -30,36 +29,19 @@ namespace EnvelopeGenerator.GeneratorAPI.Controllers;
 public class EnvelopeReceiverController : ControllerBase
 {
     private readonly ILogger<EnvelopeReceiverController> _logger;
-
-    private readonly IEnvelopeReceiverService _erService;
-
     private readonly IMediator _mediator;
-
     private readonly IMapper _mapper;
-
     private readonly IEnvelopeExecutor _envelopeExecutor;
-
     private readonly IEnvelopeReceiverExecutor _erExecutor;
-
     private readonly IDocumentExecutor _documentExecutor;
-
     private readonly string _cnnStr;
 
     /// <summary>
     /// Konstruktor für den EnvelopeReceiverController.
     /// </summary>
-    /// <param name="logger">Logger-Instanz zur Protokollierung von Informationen und Fehlern.</param>
-    /// <param name="envelopeReceiverService">Service zur Verwaltung von Umschlagempfängern.</param>
-    /// <param name="mediator">Mediator-Instanz zur Verarbeitung von Befehlen und Abfragen.</param>
-    /// <param name="mapper"></param>
-    /// <param name="envelopeExecutor"></param>
-    /// <param name="erExecutor"></param>
-    /// <param name="documentExecutor"></param>
-    /// <param name="csOpt"></param>
-    public EnvelopeReceiverController(ILogger<EnvelopeReceiverController> logger, IEnvelopeReceiverService envelopeReceiverService, IMediator mediator, IMapper mapper, IEnvelopeExecutor envelopeExecutor, IEnvelopeReceiverExecutor erExecutor, IDocumentExecutor documentExecutor, IOptions<ConnectionString> csOpt)
+    public EnvelopeReceiverController(ILogger<EnvelopeReceiverController> logger, IMediator mediator, IMapper mapper, IEnvelopeExecutor envelopeExecutor, IEnvelopeReceiverExecutor erExecutor, IDocumentExecutor documentExecutor, IOptions<ConnectionString> csOpt)
     {
         _logger = logger;
-        _erService = envelopeReceiverService;
         _mediator = mediator;
         _mapper = mapper;
         _envelopeExecutor = envelopeExecutor;
@@ -84,29 +66,11 @@ public class EnvelopeReceiverController : ControllerBase
     [HttpGet]
     public async Task<IActionResult> GetEnvelopeReceiver([FromQuery] ReadEnvelopeReceiverQuery envelopeReceiver)
     {
-        var username = User.GetUsernameOrDefault();
+        envelopeReceiver = envelopeReceiver with { Username = User.GetUsername() };
 
-        if (username is null)
-        {
-            _logger.LogError(@"Envelope Receiver dto cannot be sent because username claim is null. Potential authentication and authorization error. The value of other claims are [id: {id}], [username: {username}], [name: {name}], [prename: {prename}], [email: {email}].",
-                User.GetId(), User.GetUsernameOrDefault(), User.GetNameOrDefault(), User.GetPrenameOrDefault(), User.GetEmailOrDefault());
-            return StatusCode(StatusCodes.Status500InternalServerError);
-        }
+        var result = await _mediator.Send(envelopeReceiver);
 
-        return await _erService.ReadByUsernameAsync(
-            username: username,
-            min_status: envelopeReceiver.Status?.Min,
-            max_status: envelopeReceiver.Status?.Max,
-            envelopeQuery: envelopeReceiver.Envelope,
-            receiverQuery: envelopeReceiver.Receiver,
-            ignore_statuses: envelopeReceiver.Status?.Ignore ?? Array.Empty<int>())
-            .ThenAsync(
-                Success: Ok,
-                Fail: IActionResult (msg, ntc) =>
-                {
-                    _logger.LogNotice(ntc);
-                    return StatusCode(StatusCodes.Status500InternalServerError, msg);
-                });
+        return Ok(result);
     }
 
     /// <summary>
@@ -125,22 +89,15 @@ public class EnvelopeReceiverController : ControllerBase
     [HttpGet("salute")]
     public async Task<IActionResult> GetReceiverName([FromQuery] ReadReceiverNameQuery receiver)
     {
-        return await _erService.ReadLastUsedReceiverNameByMailAsync(receiver.EmailAddress, receiver.Id, receiver.Signature).ThenAsync(
-                        Success: res => res is null ? NotFound() : Ok(res),
-                        Fail: IActionResult (msg, ntc) =>
-                        {
-                            if (ntc.HasFlag(Flag.NotFound))
-                                return NotFound();
-
-                            _logger.LogNotice(ntc);
-                            return StatusCode(StatusCodes.Status500InternalServerError);
-                        });
+        var name = await _mediator.Send(receiver);
+        return name is null ? NotFound() : Ok(name);
     }
 
     /// <summary>
     /// Datenübertragungsobjekt mit Informationen zu Umschlägen, Empfängern und Unterschriften.
     /// </summary>
     /// <param name="request"></param>
+    /// <param name="cancel"></param>
     /// <returns>HTTP-Antwort</returns>
     /// <remarks>
     /// Sample request:
@@ -176,13 +133,10 @@ public class EnvelopeReceiverController : ControllerBase
     /// <response code="500">Es handelt sich um einen unerwarteten Fehler. Die Protokolle sollten überprüft werden.</response>
     [Authorize]
     [HttpPost]
-    public async Task<IActionResult> CreateAsync([FromBody] CreateEnvelopeReceiverCommand request)
+    public async Task<IActionResult> CreateAsync([FromBody] CreateEnvelopeReceiverCommand request, CancellationToken cancel)
     {
-        CancellationToken cancel = default;
-        int userId = User.GetId();
-
         #region Create Envelope
-        var envelope = await _envelopeExecutor.CreateEnvelopeAsync(userId, request.Title, request.Message, request.TFAEnabled, cancel);
+        var envelope = await _envelopeExecutor.CreateEnvelopeAsync(User.GetId(), request.Title, request.Message, request.TFAEnabled, cancel);
         #endregion
 
         #region Add receivers
@@ -201,7 +155,7 @@ public class EnvelopeReceiverController : ControllerBase
 
         var res = _mapper.Map<CreateEnvelopeReceiverResponse>(envelope);
         res.UnsentReceivers = unsentReceivers;
-        res.SentReceiver = _mapper.Map<List<ReceiverReadDto>>(sentReceivers.Select(er => er.Receiver));
+        res.SentReceiver = _mapper.Map<List<ReceiverDto>>(sentReceivers.Select(er => er.Receiver));
         #endregion
 
         #region Add document
@@ -227,15 +181,14 @@ public class EnvelopeReceiverController : ControllerBase
                 SELECT @OUT_SUCCESS as [@OUT_SUCCESS];";
 
         foreach (var rcv in res.SentReceiver)
-            foreach (var sign in request.Receivers.Where(r => r.EmailAddress == rcv.EmailAddress).FirstOrDefault()?.Signatures ?? Array.Empty<Signature>())
-            {
-                using (SqlConnection conn = new(_cnnStr))
+            foreach (var sign in request.Receivers.Where(r => r.EmailAddress == rcv.EmailAddress).FirstOrDefault()?.Signatures ?? Enumerable.Empty<Application.EnvelopeReceivers.Commands.Signature>())
             {
+                using SqlConnection conn = new(_cnnStr);
                 conn.Open();
 
                 var formattedSQL = string.Format(sql, document.Id.ToSqlParam(), rcv.Id.ToSqlParam(), sign.X.ToSqlParam(), sign.Y.ToSqlParam(), sign.Page.ToSqlParam());
 
-                    using SqlCommand cmd = new SqlCommand(formattedSQL, conn);
+                using SqlCommand cmd = new(formattedSQL, conn);
                 cmd.CommandType = CommandType.Text;
 
                 using SqlDataReader reader = cmd.ExecuteReader();
@@ -244,7 +197,6 @@ public class EnvelopeReceiverController : ControllerBase
                     bool outSuccess = reader.GetBoolean(0);
                 }
             }
-            }
         #endregion
 
         #region Create history
@@ -265,20 +217,16 @@ public class EnvelopeReceiverController : ControllerBase
         using (SqlConnection conn = new(_cnnStr))
         {
             conn.Open();
-            var formattedSQL_hist = string.Format(sql_hist, envelope.Uuid.ToSqlParam(), 1003.ToSqlParam(), userId.ToSqlParam());
-            using (SqlCommand cmd = new SqlCommand(formattedSQL_hist, conn))
-            {
+            var formattedSQL_hist = string.Format(sql_hist, envelope.Uuid.ToSqlParam(), 1003.ToSqlParam(), User.GetId().ToSqlParam());
+            using SqlCommand cmd = new(formattedSQL_hist, conn);
             cmd.CommandType = CommandType.Text;
 
-                using (SqlDataReader reader = cmd.ExecuteReader())
-                {
+            using SqlDataReader reader = cmd.ExecuteReader();
             if (reader.Read())
             {
                 bool outSuccess = reader.GetBoolean(0);
             }
         }
-            }
-        }
         #endregion
 
         return Ok(res);

EnvelopeGenerator.API/Controllers/EnvelopeTypeController.cs

@@ -0,0 +1,39 @@
+using MediatR;
+using EnvelopeGenerator.Application.EnvelopeTypes.Queries;
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.GeneratorAPI.Controllers;
+
+/// <summary>
+/// 
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+[Route("api/[controller]")]
+[ApiController]
+public class EnvelopeTypeController : ControllerBase
+{
+    private readonly ILogger<EnvelopeTypeController> _logger;
+    private readonly IMediator _mediator;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="logger"></param>
+    /// <param name="mediator"></param>
+    public EnvelopeTypeController(ILogger<EnvelopeTypeController> logger, IMediator mediator)
+    {
+        _logger = logger;
+        _mediator = mediator;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    [HttpGet]
+    public async Task<IActionResult> GetAllAsync()
+    {
+        var result = await _mediator.Send(new ReadEnvelopeTypesQuery());
+        return Ok(result);
+    }
+}

EnvelopeGenerator.API/Controllers/HistoryController.cs

@@ -1,13 +1,12 @@
-using EnvelopeGenerator.Application.Contracts.Services;
-using EnvelopeGenerator.Application.Histories.Queries.Read;
-using EnvelopeGenerator.Extensions;
-using MediatR;
+using MediatR;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Caching.Memory;
-using static EnvelopeGenerator.Common.Constants;
+using EnvelopeGenerator.Application.Histories.Queries;
+using EnvelopeGenerator.Domain.Constants;
+using EnvelopeGenerator.Application.Common.Extensions;
 
-namespace EnvelopeGenerator.GeneratorAPI.Controllers;
+namespace EnvelopeGenerator.API.Controllers;
 
 /// <summary>
 /// Dieser Controller stellt Endpunkte für den Zugriff auf die Umschlaghistorie bereit.
@@ -17,8 +16,6 @@ namespace EnvelopeGenerator.GeneratorAPI.Controllers;
 [Authorize]
 public class HistoryController : ControllerBase
 {
-    private readonly IEnvelopeHistoryService _service;
-
     private readonly IMemoryCache _memoryCache;
 
     private readonly IMediator _mediator;
@@ -26,23 +23,21 @@ public class HistoryController : ControllerBase
     /// <summary>
     /// Konstruktor für den HistoryController.
     /// </summary>
-    /// <param name="service">Der Dienst, der für die Verarbeitung der Umschlaghistorie verantwortlich ist.</param>
     /// <param name="memoryCache"></param>
-    /// param name="mediator"
-    public HistoryController(IEnvelopeHistoryService service, IMemoryCache memoryCache, IMediator mediator)
+    /// <param name="mediator"></param>
+    public HistoryController(IMemoryCache memoryCache, IMediator mediator)
     {
-        _service = service;
         _memoryCache = memoryCache;
         _mediator = mediator;
     }
 
     /// <summary>
-    /// Gibt alle möglichen Verweise auf alle möglichen Status in einem Verlaufsdatensatz zurück. (z. B. DocumentSigned bezieht sich auf Receiver.)
+    /// Gibt alle möglichen Verweise auf alle möglichen Include in einem Verlaufsdatensatz zurück. (z. B. DocumentSigned bezieht sich auf Receiver.)
     /// Dies wird hinzugefügt, damit Client-Anwendungen sich selbst auf dem neuesten Stand halten können.
     /// 1 - Sender:
-    /// Historische Datensätze über den Status der Empfänger. Diese haben Statuscodes, die mit 1* beginnen.
+    /// Historische Datensätze über den Include der Empfänger. Diese haben Statuscodes, die mit 1* beginnen.
     /// 2 - Receiver:
-    /// Historische Datensätze, die sich auf den Status des Absenders beziehen. Sie haben Statuscodes, die mit 2* beginnen.
+    /// Historische Datensätze, die sich auf den Include des Absenders beziehen. Sie haben Statuscodes, die mit 2* beginnen.
     /// 3 - System:
     /// Historische Datensätze, die sich auf den allgemeinen Zustand des Umschlags beziehen. Diese haben Statuscodes, die mit 3* beginnen.
     /// 4 - Unknown: 
@@ -54,11 +49,13 @@ public class HistoryController : ControllerBase
     [Authorize]
     public IActionResult GetReferenceTypes(ReferenceType? referenceType = null)
     {
-        return referenceType is null ? Ok(_memoryCache.GetEnumAsDictionary<ReferenceType>("gen.api", ReferenceType.Unknown)) : Ok(referenceType.ToString());
+        return referenceType is null 
+            ? Ok(_memoryCache.GetEnumAsDictionary<ReferenceType>("gen.api", ReferenceType.Unknown))
+            : Ok(referenceType.ToString());
     }
 
     /// <summary>
-    /// Gibt alle möglichen Status in einem Verlaufsdatensatz zurück.
+    /// Gibt alle möglichen Include in einem Verlaufsdatensatz zurück.
     /// Dies wird hinzugefügt, damit Client-Anwendungen sich selbst auf dem neuesten Stand halten können.
     /// 1003: EnvelopeQueued
     /// 1006: EnvelopeCompletelySigned
@@ -83,9 +80,9 @@ public class HistoryController : ControllerBase
     /// 3005: MessageCompletionSent
     /// </summary>
     /// <param name="status">
-    /// Abfrageparameter, der angibt, auf welche Referenz sich der Status bezieht.
-    /// 1 - Sender: Historische Datensätze, die sich auf den Status des Absenders beziehen. Sie haben Statuscodes, die mit 1* beginnen.
-    /// 2 - Receiver: Historische Datensätze über den Status der Empfänger. Diese haben Statuscodes, die mit 2* beginnen.
+    /// Abfrageparameter, der angibt, auf welche Referenz sich der Include bezieht.
+    /// 1 - Sender: Historische Datensätze, die sich auf den Include des Absenders beziehen. Sie haben Statuscodes, die mit 1* beginnen.
+    /// 2 - Receiver: Historische Datensätze über den Include der Empfänger. Diese haben Statuscodes, die mit 2* beginnen.
     /// 3 - System: Diese werden durch Datenbank-Trigger aktualisiert und sind in den Tabellen EnvelopeHistory und EmailOut zu finden.Sie arbeiten 
     /// integriert mit der Anwendung EmailProfiler, um E-Mails zu versenden und haben die Codes, die mit 3* beginnen.
     /// </param>
@@ -95,13 +92,16 @@ public class HistoryController : ControllerBase
     [Authorize]
     public IActionResult GetEnvelopeStatus([FromQuery] EnvelopeStatus? status = null)
     {
-        return status is null ? Ok(_memoryCache.GetEnumAsDictionary<EnvelopeStatus>("gen.api", Status.NonHist, Status.RelatedToFormApp)) : Ok(status.ToString());
+        return status is null
+            ? Ok(_memoryCache.GetEnumAsDictionary<EnvelopeStatus>("gen.api", Status.NonHist, Status.RelatedToFormApp))
+            : Ok(status.ToString());
     }
 
     /// <summary>
     /// Ruft die gesamte Umschlaghistorie basierend auf den angegebenen Abfrageparametern ab.
     /// </summary>
     /// <param name="historyQuery">Die Abfrageparameter, die die Filterkriterien für die Umschlaghistorie definieren.</param>
+    /// <param name="cancel"></param>
     /// <returns>Eine Liste von Historieneinträgen, die den angegebenen Kriterien entsprechen, oder nur der letzte Eintrag.</returns>
     /// <response code="200">Die Anfrage war erfolgreich, und die Umschlaghistorie wird zurückgegeben.</response>
     /// <response code="400">Die Anfrage war ungültig oder unvollständig.</response>
@@ -110,10 +110,9 @@ public class HistoryController : ControllerBase
     /// <response code="500">Ein unerwarteter Fehler ist aufgetreten.</response>
     [HttpGet]
     [Authorize]
-    public async Task<IActionResult> GetAllAsync([FromQuery] ReadHistoryQuery historyQuery)
+    public async Task<IActionResult> GetAllAsync([FromQuery] ReadHistoryQuery historyQuery, CancellationToken cancel)
     {
-        var history = await _mediator.Send(historyQuery);
-
-        return Ok((historyQuery.OnlyLast ?? false) ? history.MaxBy(h => h.AddedWhen) : history);
+        var history = await _mediator.Send(historyQuery, cancel).ThrowIfEmpty(Exceptions.NotFound);
+        return Ok((historyQuery.OnlyLast) ? history.MaxBy(h => h.AddedWhen) : history);
     }
 }

EnvelopeGenerator.API/Controllers/LocalizationController.cs

@@ -1,12 +1,12 @@
 using DigitalData.Core.API;
 using EnvelopeGenerator.Application.Resources;
-using EnvelopeGenerator.Common;
 using Microsoft.AspNetCore.Localization;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Extensions.Localization;
+using EnvelopeGenerator.Application.Resources;
 
-namespace EnvelopeGenerator.GeneratorAPI.Controllers;
+namespace EnvelopeGenerator.API.Controllers;
 
 /// <summary>
 /// Controller für die Verwaltung der Lokalisierung und Spracheinstellungen.
@@ -19,7 +19,7 @@ public class LocalizationController : ControllerBase
     private static readonly Guid L_KEY = Guid.NewGuid();
 
     private readonly ILogger<LocalizationController> _logger;
-    private readonly IStringLocalizer<Model> _mLocalizer;
+    private readonly IStringLocalizer<Resource> _mLocalizer;
     private readonly IStringLocalizer<Resource> _localizer;
     private readonly IMemoryCache _cache;
 
@@ -34,7 +34,7 @@ public class LocalizationController : ControllerBase
         ILogger<LocalizationController> logger,
         IStringLocalizer<Resource> localizer,
         IMemoryCache memoryCache,
-        IStringLocalizer<Model> _modelLocalizer)
+        IStringLocalizer<Resource> _modelLocalizer)
     {
         _logger = logger;
         _localizer = localizer;

EnvelopeGenerator.API/Controllers/ReadOnlyController.cs

@@ -0,0 +1,90 @@
+using DigitalData.Core.Abstraction.Application.DTO;
+using EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiverReadOnly;
+using EnvelopeGenerator.Application.Common.Interfaces.Services;
+using EnvelopeGenerator.Domain.Constants;
+using EnvelopeGenerator.API.Extensions;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Newtonsoft.Json;
+
+namespace EnvelopeGenerator.API.Controllers;
+
+/// <summary>
+/// Manages read-only envelope sharing flows.
+/// </summary>
+[Route("api/[controller]")]
+[ApiController]
+public class ReadOnlyController : ControllerBase
+{
+    private readonly ILogger<ReadOnlyController> _logger;
+    private readonly IEnvelopeReceiverReadOnlyService _readOnlyService;
+    private readonly IEnvelopeMailService _mailService;
+    private readonly IEnvelopeHistoryService _historyService;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ReadOnlyController"/> class.
+    /// </summary>
+    public ReadOnlyController(ILogger<ReadOnlyController> logger, IEnvelopeReceiverReadOnlyService readOnlyService, IEnvelopeMailService mailService, IEnvelopeHistoryService historyService)
+    {
+        _logger = logger;
+        _readOnlyService = readOnlyService;
+        _mailService = mailService;
+        _historyService = historyService;
+    }
+
+    /// <summary>
+    /// Creates a new read-only receiver for the current envelope.
+    /// </summary>
+    /// <param name="createDto">Creation payload.</param>
+    [HttpPost]
+    [Authorize(Roles = Role.Receiver.FullyAuth)]
+    public async Task<IActionResult> CreateAsync([FromBody] EnvelopeReceiverReadOnlyCreateDto createDto)
+    {
+        var authReceiverMail = User.GetReceiverMailOfReceiver();
+        if (authReceiverMail is null)
+        {
+            _logger.LogError("EmailAddress claim is not found in envelope-receiver-read-only creation process. Create DTO is:\n {dto}", JsonConvert.SerializeObject(createDto));
+            return Unauthorized();
+        }
+
+        var envelopeId = User.GetEnvelopeIdOfReceiver();
+
+        createDto.AddedWho = authReceiverMail;
+        createDto.EnvelopeId = envelopeId;
+
+        var creationRes = await _readOnlyService.CreateAsync(createDto: createDto);
+
+        if (creationRes.IsFailed)
+        {
+            _logger.LogNotice(creationRes);
+            return StatusCode(StatusCodes.Status500InternalServerError);
+        }
+
+        var readRes = await _readOnlyService.ReadByIdAsync(creationRes.Data.Id);
+        if (readRes.IsFailed)
+        {
+            _logger.LogNotice(creationRes);
+            return StatusCode(StatusCodes.Status500InternalServerError);
+        }
+
+        var newReadOnly = readRes.Data;
+
+        return await _mailService.SendAsync(newReadOnly).ThenAsync<int, IActionResult>(SuccessAsync: async _ =>
+        {
+            var histRes = await _historyService.RecordAsync((int)createDto.EnvelopeId, createDto.AddedWho, EnvelopeStatus.EnvelopeShared);
+            if (histRes.IsFailed)
+            {
+                _logger.LogError("Although the envelope was sent as read-only, the EnvelopeShared history could not be saved. Create DTO:\n{createDto}", JsonConvert.SerializeObject(createDto));
+                _logger.LogNotice(histRes.Notices);
+            }
+
+            return Ok();
+        },
+
+        Fail: (msg, ntc) =>
+        {
+            _logger.LogNotice(ntc);
+            return StatusCode(StatusCodes.Status500InternalServerError);
+        });
+    }
+}

EnvelopeGenerator.API/Controllers/ReceiverController.cs

@@ -0,0 +1,47 @@
+using MediatR;
+using EnvelopeGenerator.Application.Receivers.Queries;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.GeneratorAPI.Controllers;
+
+/// <summary>
+/// Controller für die Verwaltung von Empfängern.
+/// </summary>
+/// <remarks>
+/// Dieser Controller bietet Endpunkte für das Abrufen von Empfängern basierend auf E-Mail-Adresse oder Signatur.
+/// </remarks>
+[Route("api/[controller]")]
+[ApiController]
+[Authorize]
+public class ReceiverController : ControllerBase
+{
+    private readonly IMediator _mediator;
+
+    /// <summary>
+    /// Initialisiert eine neue Instanz des <see cref="ReceiverController"/>-Controllers.
+    /// </summary>
+    /// <param name="mediator">Mediator für Anfragen.</param>
+    public ReceiverController(IMediator mediator)
+    {
+        _mediator = mediator;
+    }
+
+    /// <summary>
+    /// Ruft eine Liste von Empfängern ab, basierend auf den angegebenen Abfrageparametern.
+    /// </summary>
+    /// <param name="receiver">Die Abfrageparameter, einschließlich E-Mail-Adresse und Signatur.</param>
+    /// <returns>Eine Liste von Empfängern oder ein Fehlerstatus.</returns>
+    [HttpGet]
+    public async Task<IActionResult> Get([FromQuery] ReadReceiverQuery receiver)
+    {
+        if (!receiver.HasAnyCriteria)
+        {
+            var all = await _mediator.Send(new ReadReceiverQuery());
+            return Ok(all);
+        }
+
+        var result = await _mediator.Send(receiver);
+        return result is null ? NotFound() : Ok(result);
+    }
+}

EnvelopeGenerator.API/Controllers/TfaRegistrationController.cs

@@ -0,0 +1,129 @@
+using DigitalData.Core.Abstraction.Application.DTO;
+using EnvelopeGenerator.Application.Common.Extensions;
+using EnvelopeGenerator.Application.Common.Interfaces.Services;
+using EnvelopeGenerator.Application.Resources;
+using EnvelopeGenerator.Domain.Constants;
+using EnvelopeGenerator.API.Models;
+using Ganss.Xss;
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.AspNetCore.Authentication.Cookies;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Localization;
+using Microsoft.Extensions.Options;
+
+namespace EnvelopeGenerator.API.Controllers;
+
+/// <summary>
+/// Exposes endpoints for registering and managing two-factor authentication for envelope receivers.
+/// </summary>
+[ApiController]
+[Route("api/tfa")]
+public class TfaRegistrationController : ControllerBase
+{
+    private readonly ILogger<TfaRegistrationController> _logger;
+    private readonly IEnvelopeReceiverService _envelopeReceiverService;
+    private readonly IAuthenticator _authenticator;
+    private readonly IReceiverService _receiverService;
+    private readonly TFARegParams _parameters;
+    private readonly IStringLocalizer<Resource> _localizer;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="TfaRegistrationController"/> class.
+    /// </summary>
+    public TfaRegistrationController(
+        ILogger<TfaRegistrationController> logger,
+        IEnvelopeReceiverService envelopeReceiverService,
+        IAuthenticator authenticator,
+        IReceiverService receiverService,
+        IOptions<TFARegParams> tfaRegParamsOptions,
+        IStringLocalizer<Resource> localizer)
+    {
+        _logger = logger;
+        _envelopeReceiverService = envelopeReceiverService;
+        _authenticator = authenticator;
+        _receiverService = receiverService;
+        _parameters = tfaRegParamsOptions.Value;
+        _localizer = localizer;
+    }
+
+    /// <summary>
+    /// Generates registration metadata (QR code and deadline) for a receiver.
+    /// </summary>
+    /// <param name="envelopeReceiverId">Encoded envelope receiver id.</param>
+    [Authorize]
+    [HttpGet("{envelopeReceiverId}")]
+    public async Task<IActionResult> RegisterAsync(string envelopeReceiverId)
+    {
+        try
+        {
+            var (uuid, signature) = envelopeReceiverId.DecodeEnvelopeReceiverId();
+
+            if (uuid is null || signature is null)
+            {
+                _logger.LogEnvelopeError(uuid: uuid, signature: signature, message: _localizer.WrongEnvelopeReceiverId());
+                return Unauthorized(new { message = _localizer.WrongEnvelopeReceiverId() });
+            }
+
+            var secretResult = await _envelopeReceiverService.ReadWithSecretByUuidSignatureAsync(uuid: uuid, signature: signature);
+            if (secretResult.IsFailed)
+            {
+                _logger.LogNotice(secretResult.Notices);
+                return NotFound(new { message = _localizer.WrongEnvelopeReceiverId() });
+            }
+
+            var envelopeReceiver = secretResult.Data;
+
+            if (!envelopeReceiver.Envelope!.TFAEnabled)
+                return Unauthorized(new { message = _localizer.WrongAccessCode() });
+
+            var receiver = envelopeReceiver.Receiver;
+            receiver!.TotpSecretkey = _authenticator.GenerateTotpSecretKey();
+            await _receiverService.UpdateAsync(receiver);
+            var totpQr64 = _authenticator.GenerateTotpQrCode(userEmail: receiver.EmailAddress, secretKey: receiver.TotpSecretkey).ToBase64String();
+
+            if (receiver.TfaRegDeadline is null)
+            {
+                receiver.TfaRegDeadline = _parameters.Deadline;
+                await _receiverService.UpdateAsync(receiver);
+            }
+            else if (receiver.TfaRegDeadline <= DateTime.Now)
+            {
+                return StatusCode(StatusCodes.Status410Gone, new { message = _localizer.WrongAccessCode() });
+            }
+
+            return Ok(new
+            {
+                envelopeReceiver.EnvelopeId,
+                envelopeReceiver.Envelope!.Uuid,
+                envelopeReceiver.Receiver!.Signature,
+                receiver.TfaRegDeadline,
+                TotpQR64 = totpQr64
+            });
+        }
+        catch (Exception ex)
+        {
+            _logger.LogEnvelopeError(envelopeReceiverId: envelopeReceiverId, exception: ex, message: _localizer.WrongEnvelopeReceiverId());
+            return StatusCode(StatusCodes.Status500InternalServerError, new { message = _localizer.UnexpectedError() });
+        }
+    }
+
+    /// <summary>
+    /// Logs out the envelope receiver from cookie authentication.
+    /// </summary>
+    [Authorize(Roles = Role.FullyAuth)]
+    [HttpPost("auth/logout")]
+    public async Task<IActionResult> LogOutAsync()
+    {
+        try
+        {
+            await HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
+            return Ok();
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "{message}", ex.Message);
+            return StatusCode(StatusCodes.Status500InternalServerError, new { message = _localizer.UnexpectedError() });
+        }
+    }
+}

EnvelopeGenerator.API/Documentation/AuthProxyDocumentFilter.cs

@@ -0,0 +1,70 @@
+using EnvelopeGenerator.API.Models;
+using Microsoft.OpenApi.Any;
+using Microsoft.OpenApi.Models;
+using Swashbuckle.AspNetCore.SwaggerGen;
+
+namespace EnvelopeGenerator.API.Documentation;
+
+/// <summary>
+/// 
+/// </summary>
+public sealed class AuthProxyDocumentFilter : IDocumentFilter
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="swaggerDoc"></param>
+    /// <param name="context"></param>
+    public void Apply(OpenApiDocument swaggerDoc, DocumentFilterContext context)
+    {
+        const string path = "/api/auth";
+
+        var loginSchema = context.SchemaGenerator.GenerateSchema(typeof(Login), context.SchemaRepository);
+        var loginExample = new OpenApiObject
+        {
+            ["password"] = new OpenApiString(""),
+            ["username"] = new OpenApiString("")
+        };
+
+        var operation = new OpenApiOperation
+        {
+            Summary = "Proxy login (auth-hub)",
+            Description = "Proxies the request to the auth service. Add query parameter `cookie=true|false`.",
+            Tags = [new() { Name = "Auth" }],
+            Parameters =
+            {
+                new OpenApiParameter
+                {
+                    Name = "cookie",
+                    In = ParameterLocation.Query,
+                    Required = false,
+                    Schema = new OpenApiSchema { Type = "boolean", Default = new OpenApiBoolean(true) },
+                    Example = new OpenApiBoolean(true),
+                    Description = "If true, auth service sets the auth cookie."
+                }
+            },
+            RequestBody = new OpenApiRequestBody
+            {
+                Required = true,
+                Content =
+                {
+                    ["application/json"] = new OpenApiMediaType { Schema = loginSchema, Example = loginExample },
+                    ["multipart/form-data"] = new OpenApiMediaType { Schema = loginSchema, Example = loginExample }
+                }
+            },
+            Responses =
+            {
+                ["200"] = new OpenApiResponse { Description = "OK (proxied response)" },
+                ["401"] = new OpenApiResponse { Description = "Unauthorized" }
+            }
+        };
+
+        swaggerDoc.Paths[path] = new OpenApiPathItem
+        {
+            Operations =
+            {
+                [OperationType.Post] = operation
+            }
+        };
+    }
+}

EnvelopeGenerator.API/EnvelopeClaimTypes.cs

@@ -0,0 +1,17 @@
+namespace EnvelopeGenerator.API;
+
+/// <summary>
+/// Provides custom claim types for envelope-related information.
+/// </summary>
+public static class EnvelopeClaimTypes
+{
+    /// <summary>
+    /// Claim type for the title of an envelope.
+    /// </summary>
+    public static readonly string Title = $"Envelope{nameof(Title)}";
+
+    /// <summary>
+    /// Claim type for the ID of an envelope.
+    /// </summary>
+    public static readonly string Id = $"Envelope{nameof(Id)}";
+}

EnvelopeGenerator.API/EnvelopeGenerator.API.csproj

@@ -17,20 +17,29 @@
 	<DocumentationFile>bin\$(Configuration)\$(TargetFramework)\$(AssemblyName).xml</DocumentationFile>
   </PropertyGroup>
 
+  <ItemGroup>
+    <Compile Remove="ClientApp\**" />
+    <Content Remove="ClientApp\**" />
+    <EmbeddedResource Remove="ClientApp\**" />
+    <None Remove="ClientApp\**" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <None Include="yarp.json" CopyToOutputDirectory="PreserveNewest" />
+  </ItemGroup>
+
   <ItemGroup>
     <PackageReference Include="AspNetCore.Scalar" Version="1.1.8" />
     <PackageReference Include="DigitalData.Auth.Client" Version="1.3.7" />
-    <PackageReference Include="DigitalData.Core.API" Version="2.1.1" />
+    <PackageReference Include="DigitalData.Core.API" Version="2.2.1" />
     <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="9.0.4" />
-    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="9.0.4" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="9.0.6" />
     <PackageReference Include="NLog" Version="5.2.5" />
     <PackageReference Include="NLog.Web.AspNetCore" Version="5.3.0" />
     <PackageReference Include="Scalar.AspNetCore" Version="2.2.1" />
     <PackageReference Include="Swashbuckle.AspNetCore" Version="8.1.1" />
-    <PackageReference Include="DigitalData.Core.Abstractions" Version="3.6.0" />
-    <PackageReference Include="DigitalData.Core.Application" Version="3.2.1" />
-    <PackageReference Include="DigitalData.Core.DTO" Version="2.0.1" />
-    <PackageReference Include="DigitalData.EmailProfilerDispatcher.Abstraction" Version="3.0.0" />
+    <PackageReference Include="DigitalData.EmailProfilerDispatcher.Abstraction" Version="3.2.0" />
+    <PackageReference Include="Yarp.ReverseProxy" Version="2.1.0" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net7.0'">
@@ -52,41 +61,13 @@
   </ItemGroup>
 
   <ItemGroup>
-    <Folder Include="ClientApp\" />
+    <Folder Include="wwwroot\" />
   </ItemGroup>
 
   <ItemGroup>
     <ProjectReference Include="..\EnvelopeGenerator.Application\EnvelopeGenerator.Application.csproj" />
-    <ProjectReference Include="..\EnvelopeGenerator.Common\EnvelopeGenerator.Common.vbproj" />
     <ProjectReference Include="..\EnvelopeGenerator.Domain\EnvelopeGenerator.Domain.csproj" />
     <ProjectReference Include="..\EnvelopeGenerator.Infrastructure\EnvelopeGenerator.Infrastructure.csproj" />
   </ItemGroup>
 
-  <ItemGroup>
-    <None Update="ClientApp\envelope-generator-ui\dist\envelope-generator-ui\browser\chunk-35PBLQEP.js">
-      <CopyToOutputDirectory>Never</CopyToOutputDirectory>
-    </None>
-    <None Update="ClientApp\envelope-generator-ui\dist\envelope-generator-ui\browser\chunk-IUSOII6E.js">
-      <CopyToOutputDirectory>Never</CopyToOutputDirectory>
-    </None>
-    <None Update="ClientApp\envelope-generator-ui\dist\envelope-generator-ui\browser\favicon.ico">
-      <CopyToOutputDirectory>Never</CopyToOutputDirectory>
-    </None>
-    <None Update="ClientApp\envelope-generator-ui\dist\envelope-generator-ui\browser\index.html">
-      <CopyToOutputDirectory>Never</CopyToOutputDirectory>
-    </None>
-    <None Update="ClientApp\envelope-generator-ui\dist\envelope-generator-ui\browser\login\index.html">
-      <CopyToOutputDirectory>Never</CopyToOutputDirectory>
-    </None>
-    <None Update="ClientApp\envelope-generator-ui\dist\envelope-generator-ui\browser\main-ZN7C4PGY.js">
-      <CopyToOutputDirectory>Never</CopyToOutputDirectory>
-    </None>
-    <None Update="ClientApp\envelope-generator-ui\dist\envelope-generator-ui\browser\polyfills-N6LQB2YD.js">
-      <CopyToOutputDirectory>Never</CopyToOutputDirectory>
-    </None>
-    <None Update="ClientApp\envelope-generator-ui\dist\envelope-generator-ui\browser\styles-S5ZWIC2V.css">
-      <CopyToOutputDirectory>Never</CopyToOutputDirectory>
-    </None>
-  </ItemGroup>
-
 </Project>

EnvelopeGenerator.API/Extensions/ReceiverClaimExtensions.cs

@@ -0,0 +1,101 @@
+using System.Linq;
+using System.Security.Claims;
+using EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiver;
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.AspNetCore.Authentication.Cookies;
+
+namespace EnvelopeGenerator.API.Extensions;
+
+/// <summary>
+/// Provides helper methods for working with envelope-specific authentication claims.
+/// </summary>
+public static class ReceiverClaimExtensions
+{
+    private static string GetRequiredClaimOfReceiver(this ClaimsPrincipal user, string claimType)
+    {
+        var value = user.FindFirstValue(claimType);
+        if (value is not null)
+        {
+            return value;
+        }
+
+        var identity = user.Identity;
+        var principalName = identity?.Name ?? "(anonymous)";
+        var authType = identity?.AuthenticationType ?? "(none)";
+        var availableClaims = string.Join(", ", user.Claims.Select(c => $"{c.Type}={c.Value}"));
+        var message = $"Required claim '{claimType}' is missing for user '{principalName}' (auth: {authType}). Available claims: [{availableClaims}].";
+        throw new InvalidOperationException(message);
+    }
+
+    /// <summary>
+    /// Gets the authenticated envelope UUID from the claims.
+    /// </summary>
+    public static string GetEnvelopeUuidOfReceiver(this ClaimsPrincipal user) => user.GetRequiredClaimOfReceiver(ClaimTypes.NameIdentifier);
+
+    /// <summary>
+    /// Gets the authenticated receiver signature from the claims.
+    /// </summary>
+    public static string GetReceiverSignatureOfReceiver(this ClaimsPrincipal user) => user.GetRequiredClaimOfReceiver(ClaimTypes.Hash);
+
+    /// <summary>
+    /// Gets the authenticated receiver display name from the claims.
+    /// </summary>
+    public static string GetReceiverNameOfReceiver(this ClaimsPrincipal user) => user.GetRequiredClaimOfReceiver(ClaimTypes.Name);
+
+    /// <summary>
+    /// Gets the authenticated receiver email address from the claims.
+    /// </summary>
+    public static string GetReceiverMailOfReceiver(this ClaimsPrincipal user) => user.GetRequiredClaimOfReceiver(ClaimTypes.Email);
+
+    /// <summary>
+    /// Gets the authenticated envelope title from the claims.
+    /// </summary>
+    public static string GetEnvelopeTitleOfReceiver(this ClaimsPrincipal user) => user.GetRequiredClaimOfReceiver(EnvelopeClaimTypes.Title);
+
+    /// <summary>
+    /// Gets the authenticated envelope identifier from the claims.
+    /// </summary>
+    public static int GetEnvelopeIdOfReceiver(this ClaimsPrincipal user)
+    {
+        var envIdStr = user.GetRequiredClaimOfReceiver(EnvelopeClaimTypes.Id);
+        if (!int.TryParse(envIdStr, out var envId))
+        {
+            throw new InvalidOperationException($"Claim '{EnvelopeClaimTypes.Id}' is not a valid integer.");
+        }
+
+        return envId;
+    }
+
+    /// <summary>
+    /// Signs in an envelope receiver using cookie authentication and attaches envelope claims.
+    /// </summary>
+    /// <param name="context">The current HTTP context.</param>
+    /// <param name="envelopeReceiver">Envelope receiver DTO to extract claims from.</param>
+    /// <param name="receiverRole">Role to attach to the authentication ticket.</param>
+    public static async Task SignInEnvelopeAsync(this HttpContext context, EnvelopeReceiverDto envelopeReceiver, string receiverRole)
+    {
+        var claims = new List<Claim>
+        {
+            new(ClaimTypes.NameIdentifier, envelopeReceiver.Envelope!.Uuid),
+            new(ClaimTypes.Hash, envelopeReceiver.Receiver!.Signature),
+            new(ClaimTypes.Name, envelopeReceiver.Name ?? string.Empty),
+            new(ClaimTypes.Email, envelopeReceiver.Receiver.EmailAddress),
+            new(EnvelopeClaimTypes.Title, envelopeReceiver.Envelope.Title),
+            new(EnvelopeClaimTypes.Id, envelopeReceiver.Envelope.Id.ToString()),
+            new(ClaimTypes.Role, receiverRole)
+        };
+
+        var claimsIdentity = new ClaimsIdentity(claims, CookieAuthenticationDefaults.AuthenticationScheme);
+
+        var authProperties = new AuthenticationProperties
+        {
+            AllowRefresh = false,
+            IsPersistent = false
+        };
+
+        await context.SignInAsync(
+            CookieAuthenticationDefaults.AuthenticationScheme,
+            new ClaimsPrincipal(claimsIdentity),
+            authProperties);
+    }
+}

EnvelopeGenerator.API/Extensions/SenderClaimExtensions.cs

@@ -0,0 +1,95 @@
+using System.Security.Claims;
+
+namespace EnvelopeGenerator.API.Extensions
+{
+    /// <summary>
+    /// Provides extension methods for extracting user information from a <see cref="ClaimsPrincipal"/>.
+    /// </summary>
+    public static class SenderClaimExtensions
+    {
+        private static string GetRequiredClaimOfSender(this ClaimsPrincipal user, string claimType)
+        {
+            var value = user.FindFirstValue(claimType);
+            if (value is not null)
+            {
+                return value;
+            }
+
+            var identity = user.Identity;
+            var principalName = identity?.Name ?? "(anonymous)";
+            var authType = identity?.AuthenticationType ?? "(none)";
+            var availableClaims = string.Join(", ", user.Claims.Select(c => $"{c.Type}={c.Value}"));
+            var message = $"Required claim '{claimType}' is missing for user '{principalName}' (auth: {authType}). Available claims: [{availableClaims}].";
+            throw new InvalidOperationException(message);
+        }
+
+        private static string GetRequiredClaimOfSender(this ClaimsPrincipal user, params string[] claimTypes)
+        {
+            string? value = null;
+
+            foreach (var claimType in claimTypes)
+            {
+                value = user.FindFirstValue(claimType);
+                if (value is not null)
+                    return value;
+            }
+
+            var identity = user.Identity;
+            var principalName = identity?.Name ?? "(anonymous)";
+            var authType = identity?.AuthenticationType ?? "(none)";
+            var availableClaims = string.Join(", ", user.Claims.Select(c => $"{c.Type}={c.Value}"));
+            var message = $"Required claim among [{string.Join(", ", claimTypes)}] is missing for user '{principalName}' (auth: {authType}). Available claims: [{availableClaims}].";
+            throw new InvalidOperationException(message);
+        }
+
+        /// <summary>
+        /// Retrieves the user's ID from the claims. Throws an exception if the ID is missing or invalid.
+        /// </summary>
+        /// <param name="user">The <see cref="ClaimsPrincipal"/> representing the user.</param>
+        /// <returns>The user's ID as an integer.</returns>
+        /// <exception cref="InvalidOperationException">Thrown if the user ID claim is missing or invalid.</exception>
+        public static int GetId(this ClaimsPrincipal user)
+        {
+            var idValue = user.GetRequiredClaimOfSender(ClaimTypes.NameIdentifier, "sub");
+
+            if (!int.TryParse(idValue, out var result))
+            {
+                throw new InvalidOperationException("User ID claim is missing or invalid. This may indicate a misconfigured or forged JWT token.");
+            }
+
+            return result;
+        }
+
+        /// <summary>
+        /// Retrieves the username from the claims.
+        /// </summary>
+        /// <param name="user">The <see cref="ClaimsPrincipal"/> representing the user.</param>
+        /// <returns>The username as a string.</returns>
+        public static string GetUsername(this ClaimsPrincipal user)
+            => user.GetRequiredClaimOfSender(ClaimTypes.Name);
+
+        /// <summary>
+        /// Retrieves the user's surname (last name) from the claims.
+        /// </summary>
+        /// <param name="user">The <see cref="ClaimsPrincipal"/> representing the user.</param>
+        /// <returns>The surname as a string.</returns>
+        public static string GetName(this ClaimsPrincipal user)
+            => user.GetRequiredClaimOfSender(ClaimTypes.Surname);
+
+        /// <summary>
+        /// Retrieves the user's given name (first name) from the claims.
+        /// </summary>
+        /// <param name="user">The <see cref="ClaimsPrincipal"/> representing the user.</param>
+        /// <returns>The given name as a string.</returns>
+        public static string GetPrename(this ClaimsPrincipal user)
+            => user.GetRequiredClaimOfSender(ClaimTypes.GivenName);
+
+        /// <summary>
+        /// Retrieves the user's email address from the claims.
+        /// </summary>
+        /// <param name="user">The <see cref="ClaimsPrincipal"/> representing the user.</param>
+        /// <returns>The email address as a string.</returns>
+        public static string GetEmail(this ClaimsPrincipal user)
+            => user.GetRequiredClaimOfSender(ClaimTypes.Email);
+    }
+}

EnvelopeGenerator.API/Middleware/ExceptionHandlingMiddleware.cs

@@ -1,6 +1,6 @@
-namespace EnvelopeGenerator.GeneratorAPI.Middleware;
+namespace EnvelopeGenerator.API.Middleware;
 
-using EnvelopeGenerator.Application.Exceptions;
+using DigitalData.Core.Exceptions;
 using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Logging;
 using System.Net;

EnvelopeGenerator.API/Models/Auth.cs

@@ -0,0 +1,14 @@
+namespace EnvelopeGenerator.API.Models;
+
+public record Auth(string? AccessCode = null, string? SmsCode = null, string? AuthenticatorCode = null, bool UserSelectSMS = default)
+{
+    public bool HasAccessCode => AccessCode is not null;
+
+    public bool HasSmsCode => SmsCode is not null;
+
+    public bool HasAuthenticatorCode => AuthenticatorCode is not null;
+
+    public bool HasMulti => new[] { HasAccessCode, HasSmsCode, HasAuthenticatorCode }.Count(state => state) > 1;
+
+    public bool HasNone => !(HasAccessCode || HasSmsCode || HasAuthenticatorCode);
+}

EnvelopeGenerator.API/Models/AuthTokenKeys.cs

@@ -1,4 +1,4 @@
-namespace EnvelopeGenerator.GeneratorAPI.Models;
+namespace EnvelopeGenerator.API.Models;
 
 /// <summary>
 /// Represents the keys and default values used for authentication token handling 
@@ -24,5 +24,5 @@ public class AuthTokenKeys
     /// <summary>
     /// Gets the expected audience value for the authentication token.
     /// </summary>
-    public string Audience { get; init; } = "sign-flow-gen.digitaldata.works";
+    public string Audience { get; init; } = "sign-flow.digitaldata.works";
 }

EnvelopeGenerator.API/Models/ConnectionString.cs

@@ -1,4 +1,4 @@
-namespace EnvelopeGenerator.GeneratorAPI.Models;
+namespace EnvelopeGenerator.API.Models;
 
 /// <summary>
 /// 

EnvelopeGenerator.API/Models/ContactLink.cs

@@ -0,0 +1,60 @@
+namespace EnvelopeGenerator.API.Models
+{
+    /// <summary>
+    /// Represents a hyperlink for contact purposes with various HTML attributes.
+    /// </summary>
+    public class ContactLink
+    {
+        /// <summary>
+        /// Gets or sets the label of the hyperlink.
+        /// </summary>
+        public string Label { get; init; } = "Contact";
+
+        /// <summary>
+        /// Gets or sets the URL that the hyperlink points to.
+        /// </summary>
+        public string Href { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the target where the hyperlink should open.
+        /// Commonly used values are "_blank", "_self", "_parent", "_top".
+        /// </summary>
+        public string Target { get; set; } = "_blank";
+
+        /// <summary>
+        /// Gets or sets the relationship of the linked URL as space-separated link types.
+        /// Examples include "nofollow", "noopener", "noreferrer".
+        /// </summary>
+        public string Rel { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the filename that should be downloaded when clicking the hyperlink.
+        /// This attribute will only have an effect if the href attribute is set.
+        /// </summary>
+        public string Download { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the language of the linked resource. Useful when linking to
+        /// content in another language.
+        /// </summary>
+        public string HrefLang { get; set; } = "en";
+
+        /// <summary>
+        /// Gets or sets the MIME type of the linked URL. Helps browsers to handle
+        /// the type correctly when the link is clicked.
+        /// </summary>
+        public string Type { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets additional information about the hyperlink, typically viewed
+        /// as a tooltip when the mouse hovers over the link.
+        /// </summary>
+        public string Title { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets an identifier for the hyperlink, unique within the HTML document.
+        /// </summary>
+        public string Id { get; set; } = string.Empty;
+    }
+
+}

EnvelopeGenerator.API/Models/Culture.cs

@@ -0,0 +1,17 @@
+using System.Globalization;
+
+namespace EnvelopeGenerator.API.Models;
+
+public class Culture
+{
+    private string _language = string.Empty;
+    public string Language { get => _language;
+        init {
+            _language = value;
+            Info = new(value);
+        } 
+    }
+    public string FIClass { get; init; } = string.Empty;
+
+    public CultureInfo? Info { get; init; }
+}

EnvelopeGenerator.API/Models/Cultures.cs

@@ -0,0 +1,12 @@
+namespace EnvelopeGenerator.API.Models;
+
+public class Cultures : List<Culture>
+{
+    public IEnumerable<string> Languages => this.Select(c => c.Language);
+
+    public IEnumerable<string> FIClasses => this.Select(c => c.FIClass);
+
+    public Culture Default => this.First();
+    
+    public Culture? this[string? language] => language is null ? null : this.Where(c => c.Language == language).FirstOrDefault();
+}

EnvelopeGenerator.API/Models/CustomImages.cs

@@ -0,0 +1,6 @@
+namespace EnvelopeGenerator.API.Models;
+
+public class CustomImages : Dictionary<string, Image>
+{
+    public new Image this[string key] => TryGetValue(key, out var img) && img is not null ? img : new();
+}

EnvelopeGenerator.API/Models/ErrorViewModel.cs

@@ -0,0 +1,10 @@
+namespace EnvelopeGenerator.API.Models;
+
+public class ErrorViewModel
+{
+    public string Title { get; init; } = "404";
+
+    public string Subtitle { get; init; } = "Hmmm...";
+
+    public string Body { get; init; } = "It looks like one of the developers fell asleep";
+}

EnvelopeGenerator.API/Models/Image.cs

@@ -0,0 +1,10 @@
+namespace EnvelopeGenerator.API.Models;
+
+public class Image
+{
+    public string Src { get; init; } = string.Empty;
+
+    public Dictionary<string, string> Classes { get; init; } = new();
+
+    public string GetClassIn(string page) => Classes.TryGetValue(page, out var cls) && cls is not null ? cls : string.Empty;
+}

EnvelopeGenerator.API/Models/Login.cs

@@ -1,6 +1,6 @@
 using System.ComponentModel.DataAnnotations;
 
-namespace EnvelopeGenerator.GeneratorAPI.Models;
+namespace EnvelopeGenerator.API.Models;
 
 /// <summary>
 /// Repräsentiert ein Login-Modell mit erforderlichem Passwort und optionaler ID und Benutzername.

EnvelopeGenerator.API/Models/MainViewModel.cs

@@ -0,0 +1,6 @@
+namespace EnvelopeGenerator.API.Models;
+
+public class MainViewModel
+{
+    public string? Title { get; init; }
+}

EnvelopeGenerator.API/Models/PsPdfKitAnnotation/Annotation.cs

@@ -0,0 +1,93 @@
+using EnvelopeGenerator.API.Models.PsPdfKitAnnotation;
+using System.Text.Json.Serialization;
+
+namespace EnvelopeGenerator.API.Models.PsPdfKitAnnotation;
+
+public record Annotation : IAnnotation
+{
+    public required string Name { get; init; }
+
+    #region Bound Annotation
+    [JsonIgnore]
+    public string? HorBoundAnnotName { get; init; }
+
+    [JsonIgnore]
+    public string? VerBoundAnnotName { get; init; }
+    #endregion
+
+    #region Layout
+    [JsonIgnore]
+    public double? MarginLeft { get; set; }
+
+    [JsonIgnore]
+    public double MarginLeftRatio { get; init; } = 1;
+
+    [JsonIgnore]
+    public double? MarginTop { get; set; }
+
+    [JsonIgnore]
+    public double MarginTopRatio { get; init; } = 1;
+
+    public double? Width { get; set; }
+
+    [JsonIgnore]
+    public double WidthRatio { get; init; } = 1;
+
+    public double? Height { get; set; }
+
+    [JsonIgnore]
+    public double HeightRatio { get; init; } = 1;
+    #endregion
+
+    #region Position
+    public double Left => (MarginLeft ?? 0) + (HorBoundAnnot?.HorBoundary ?? 0);
+
+    public double Top => (MarginTop ?? 0) + (VerBoundAnnot?.VerBoundary ?? 0);
+    #endregion
+
+    #region Boundary
+    [JsonIgnore]
+    public double HorBoundary => Left + (Width ?? 0);
+
+    [JsonIgnore]
+    public double VerBoundary => Top + (Height ?? 0);
+    #endregion
+
+    #region BoundAnnot
+    [JsonIgnore]
+    public Annotation? HorBoundAnnot { get; set; }
+
+    [JsonIgnore]
+    public Annotation? VerBoundAnnot { get; set; }
+    #endregion
+
+    public Color? BackgroundColor { get; init; }
+
+    #region Border
+    public Color? BorderColor { get; init; }
+
+    public string? BorderStyle { get; init; }
+
+    public int? BorderWidth { get; set; }
+    #endregion
+
+    [JsonIgnore]
+    internal Annotation Default 
+    { 
+        set 
+        {
+            // To set null value, annotation must have null (0) value but null must has non-null value
+            if (MarginLeft == null && value.MarginLeft != null)
+                MarginLeft = value.MarginLeft * MarginLeftRatio;
+
+            if (MarginTop == null && value.MarginTop != null)
+                MarginTop = value.MarginTop * MarginTopRatio;
+
+            if (Width == null && value.Width != null)
+                Width = value.Width * WidthRatio;
+
+            if (Height == null && value.Height != null)
+                Height = value.Height * HeightRatio;
+        }
+    }
+};

EnvelopeGenerator.API/Models/PsPdfKitAnnotation/AnnotationParams.cs

@@ -0,0 +1,80 @@
+using EnvelopeGenerator.API.Models.PsPdfKitAnnotation;
+using System.Text.Json.Serialization;
+
+namespace EnvelopeGenerator.API.Models.PsPdfKitAnnotation;
+
+public class AnnotationParams
+{
+    public AnnotationParams()
+    {
+        _AnnotationJSObjectInitor = new(CreateAnnotationJSObject);
+    }
+
+    public Background? Background { get; init; }
+
+    #region Annotation
+    [JsonIgnore]
+    public Annotation? DefaultAnnotation { get; init; }
+
+    private readonly List<Annotation> _annots = new List<Annotation>();
+
+    public bool TryGet(string name, out Annotation annotation)
+    {
+#pragma warning disable CS8601 // Possible null reference assignment.
+        annotation = _annots.FirstOrDefault(a => a.Name == name);
+#pragma warning restore CS8601 // Possible null reference assignment.
+        return annotation is not null;
+    }
+
+    public required IEnumerable<Annotation> Annotations
+    {
+        get => _annots;
+        init
+        {
+            _annots = value.ToList();
+
+            if (DefaultAnnotation is not null)
+                foreach (var annot in _annots)
+                    annot.Default = DefaultAnnotation;
+
+            for (int i = 0; i < _annots.Count; i++)
+            {
+                #region set bound annotations
+                // horizontal
+                if (_annots[i].HorBoundAnnotName is string horBoundAnnotName)
+                    if (TryGet(horBoundAnnotName, out var horBoundAnnot))
+                        _annots[i].HorBoundAnnot = horBoundAnnot;
+                    else
+                        throw new InvalidOperationException($"{horBoundAnnotName} added as bound anotation. However, it is not defined.");
+
+                // vertical
+                if (_annots[i].VerBoundAnnotName is string verBoundAnnotName)
+                    if (TryGet(verBoundAnnotName, out var verBoundAnnot))
+                        _annots[i].VerBoundAnnot = verBoundAnnot;
+                    else
+                        throw new InvalidOperationException($"{verBoundAnnotName} added as bound anotation. However, it is not defined.");
+                #endregion
+            }
+        }
+    }
+    #endregion
+
+    #region AnnotationJSObject
+    private Dictionary<string, IAnnotation> CreateAnnotationJSObject()
+    {
+        var dict = _annots.ToDictionary(a => a.Name.ToLower(), a => a as IAnnotation);
+
+        if (Background is not null)
+        {
+            Background.Locate(_annots);
+            dict.Add(Background.Name.ToLower(), Background);
+        }            
+
+        return dict;
+    }
+
+    private readonly Lazy<Dictionary<string, IAnnotation>> _AnnotationJSObjectInitor;
+
+    public Dictionary<string, IAnnotation> AnnotationJSObject => _AnnotationJSObjectInitor.Value;
+    #endregion
+}

EnvelopeGenerator.API/Models/PsPdfKitAnnotation/Background.cs

@@ -0,0 +1,58 @@
+using System.Text.Json.Serialization;
+
+namespace EnvelopeGenerator.API.Models.PsPdfKitAnnotation;
+
+/// <summary>
+/// The Background is an annotation for the PSPDF Kit. However, it has no function.
+/// It is only the first annotation as a background for other annotations.
+/// </summary>
+public record Background : IAnnotation
+{
+    [JsonIgnore]
+    public double Margin { get; init; }
+
+    public string Name { get; } = "Background";
+
+    public double? Width { get; set; }
+
+    public double? Height { get; set; }
+
+    public double Left { get; set; }
+
+    public double Top { get; set; }
+
+    public Color? BackgroundColor { get; init; }
+
+    #region Border
+    public Color? BorderColor { get; init; }
+
+    public string? BorderStyle { get; init; }
+
+    public int? BorderWidth { get; set; }
+    #endregion
+
+    public void Locate(IEnumerable<IAnnotation> annotations)
+    {
+        // set Top
+        if (annotations.MinBy(a => a.Top)?.Top is double minTop)
+            Top = minTop;
+
+        // set Left
+        if (annotations.MinBy(a => a.Left)?.Left is double minLeft)
+            Left = minLeft;
+
+        // set Width
+        if(annotations.MaxBy(a => a.GetRight())?.GetRight() is double maxRight)
+            Width = maxRight - Left;
+
+        // set Height
+        if (annotations.MaxBy(a => a.GetBottom())?.GetBottom() is double maxBottom)
+            Height = maxBottom - Top;
+
+        // add margins
+        Top -= Margin;
+        Left -= Margin;
+        Width += Margin * 2;
+        Height += Margin * 2;
+    }
+}

EnvelopeGenerator.API/Models/PsPdfKitAnnotation/Color.cs

@@ -0,0 +1,10 @@
+namespace EnvelopeGenerator.API.Models.PsPdfKitAnnotation;
+
+public record Color
+{
+    public int R { get; init; } = 0;
+
+    public int G { get; init; } = 0;
+
+    public int B { get; init; } = 0;
+}

EnvelopeGenerator.API/Models/PsPdfKitAnnotation/Extensions.cs

@@ -0,0 +1,8 @@
+namespace EnvelopeGenerator.API.Models.PsPdfKitAnnotation;
+
+public static class Extensions
+{
+    public static double GetRight(this IAnnotation annotation) => annotation.Left + annotation?.Width ?? 0;
+
+    public static double GetBottom(this IAnnotation annotation) => annotation.Top + annotation?.Height ?? 0;
+}

EnvelopeGenerator.API/Models/PsPdfKitAnnotation/IAnnotation.cs

@@ -0,0 +1,22 @@
+namespace EnvelopeGenerator.API.Models.PsPdfKitAnnotation;
+
+public interface IAnnotation
+{
+    string Name { get; }
+
+    double? Width { get; }
+
+    double? Height { get; }
+
+    double Left { get; }
+
+    double Top { get; }
+
+    Color? BackgroundColor { get; }
+
+    Color? BorderColor { get; }
+
+    string? BorderStyle { get; }
+
+    int? BorderWidth { get; }
+}

EnvelopeGenerator.API/Models/TFARegParams.cs

@@ -0,0 +1,17 @@
+namespace EnvelopeGenerator.API.Models;
+
+/// <summary>
+/// Represents the parameters for two-factor authentication (2FA) registration.
+/// </summary>
+public class TFARegParams
+{
+    /// <summary>
+    /// The maximum allowed time for completing the registration process.
+    /// </summary>
+    public TimeSpan TimeLimit { get; init; } = new(0, 30, 0);
+
+    /// <summary>
+    /// The deadline for registration, calculated as the current time plus the <see cref="TimeLimit"/>.
+    /// </summary>
+    public DateTime Deadline => DateTime.Now.AddTicks(TimeLimit.Ticks);
+}

EnvelopeGenerator.API/Program.cs

@@ -11,11 +11,11 @@ using DigitalData.UserManager.DependencyInjection;
 using EnvelopeGenerator.Application;
 using DigitalData.Auth.Client;
 using DigitalData.Core.Abstractions;
-using EnvelopeGenerator.GeneratorAPI.Models;
+using EnvelopeGenerator.API.Models;
 using Microsoft.AspNetCore.Authentication.JwtBearer;
 using Microsoft.IdentityModel.Tokens;
 using DigitalData.Core.Abstractions.Security.Extensions;
-using EnvelopeGenerator.GeneratorAPI.Middleware;
+using EnvelopeGenerator.API.Middleware;
 using NLog.Web;
 using NLog;
 
@@ -26,6 +26,8 @@ try
 {
     var builder = WebApplication.CreateBuilder(args);
 
+    builder.Configuration.AddJsonFile("yarp.json", optional: true, reloadOnChange: true);
+
     builder.Logging.SetMinimumLevel(Microsoft.Extensions.Logging.LogLevel.Trace);
 
     if (!builder.Environment.IsDevelopment())
@@ -39,8 +41,10 @@ try
     var deferredProvider = new DeferredServiceProvider();
 
     builder.Services.AddControllers();
+    builder.Services.AddHttpClient();
+    builder.Services.AddReverseProxy().LoadFromConfig(builder.Configuration.GetSection("ReverseProxy"));
 
-    //CORS Policy
+    // CORS Policy
     var allowedOrigins = config.GetSection("AllowedOrigins").Get<string[]>() ??
         throw new InvalidOperationException("AllowedOrigins section is missing in the configuration.");
     builder.Services.AddCors(options =>
@@ -93,7 +97,7 @@ try
                     Id = "Bearer"
                 }
             },
-            new string[] {}
+            Array.Empty<string>()
         }
     });
 
@@ -102,10 +106,16 @@ try
         {
             options.IncludeXmlComments(xmlFile);
         }
+
+        options.DocumentFilter<EnvelopeGenerator.API.Documentation.AuthProxyDocumentFilter>();
     });
     builder.Services.AddOpenApi();
-    // DbContext
-    var connStr = config.GetConnectionString("Default") ?? throw new InvalidOperationException("There is no default connection string in appsettings.json.");
+
+    //AddEF Core dbcontext
+    var useDbMigration = Environment.GetEnvironmentVariable("MIGRATION_TEST_MODE") == true.ToString() || config.GetValue<bool>("UseDbMigration");
+    var cnnStrName = useDbMigration ? "DbMigrationTest" : "Default";
+    var connStr = config.GetConnectionString(cnnStrName)
+        ?? throw new InvalidOperationException($"Connection string '{cnnStrName}' is missing in the application configuration.");
 
     builder.Services.Configure<ConnectionString>(cs => cs.Value = connStr);
 
@@ -129,7 +139,7 @@ try
                 {
                     var clientParams = deferredProvider.GetOptions<ClientParams>();
                     var publicKey = clientParams!.PublicKeys.Get(authTokenKeys.Issuer, authTokenKeys.Audience);
-                    return new List<SecurityKey>() { publicKey.SecurityKey };
+                    return [publicKey.SecurityKey];
                 },
                 ValidateIssuer = true,
                 ValidIssuer = authTokenKeys.Issuer,
@@ -167,7 +177,9 @@ try
     });
 
     // User manager
+#pragma warning disable CS0618 // Type or member is obsolete
     builder.Services.AddUserManager<EGDbContext>();
+#pragma warning restore CS0618 // Type or member is obsolete
 
     // LDAP
     builder.ConfigureBySection<DirectorySearchOptions>();
@@ -177,9 +189,23 @@ try
     builder.Services.AddCookieBasedLocalizer();
 
     // Envelope generator serives
+#pragma warning disable CS0618 // Type or member is obsolete
     builder.Services
-        .AddEnvelopeGeneratorInfrastructureServices(sqlExecutorConfigureOptions: executor => executor.ConnectionString = connStr)
+        .AddEnvelopeGeneratorInfrastructureServices(opt =>
+        {
+            opt.AddDbTriggerParams(config);
+            opt.AddDbContext((provider, options) =>
+            {
+                var logger = provider.GetRequiredService<ILogger<EGDbContext>>();
+                options.UseSqlServer(connStr)
+                        .LogTo(log => logger.LogInformation("{log}", log), Microsoft.Extensions.Logging.LogLevel.Trace)
+                        .EnableSensitiveDataLogging()
+                        .EnableDetailedErrors();
+            });
+            opt.AddSQLExecutor(executor => executor.ConnectionString = connStr);
+        })
         .AddEnvelopeGeneratorServices(config);
+#pragma warning restore CS0618 // Type or member is obsolete
 
     var app = builder.Build();
 
@@ -201,10 +227,10 @@ try
     app.UseCors("AllowSpecificOriginsPolicy");
 
     // Localizer
-    string[] supportedCultureNames = { "de-DE", "en-US" };
-    IList<CultureInfo> list = supportedCultureNames.Select((string cn) => new CultureInfo(cn)).ToList();
-    CultureInfo cultureInfo = list.FirstOrDefault() ?? throw new ArgumentNullException("supportedCultureNames", "Supported cultures cannot be empty.");
-    RequestLocalizationOptions requestLocalizationOptions = new RequestLocalizationOptions
+    string[] supportedCultureNames = ["de-DE", "en-US"];
+    IList<CultureInfo> list = [.. supportedCultureNames.Select(cn => new CultureInfo(cn))];
+    var cultureInfo = list.FirstOrDefault() ?? throw new InvalidOperationException("There is no supported culture.");
+    var requestLocalizationOptions = new RequestLocalizationOptions
     {
         SupportedCultures = list,
         SupportedUICultures = list
@@ -221,6 +247,7 @@ try
     app.UseAuthentication();
     app.UseAuthorization();
 
+    app.MapReverseProxy();
     app.MapControllers();
 
     app.Run();

EnvelopeGenerator.API/appsettings.Development.json

@@ -6,11 +6,11 @@
     }
   },
   "AuthClientParams": {
-    "Url": "https://localhost:7192/auth-hub",
+    "Url": "http://172.24.12.39:9090/auth-hub",
     "PublicKeys": [
       {
         "Issuer": "auth.digitaldata.works",
-        "Audience": "sign-flow-gen.digitaldata.works"
+        "Audience": "sign-flow.digitaldata.works"
       }
     ],
     "RetryDelay": "00:00:05"

EnvelopeGenerator.API/appsettings.json

@@ -1,5 +1,6 @@
 {
   "UseSwagger": true,
+  "UseDbMigration": true,
   "DiPMode": true,
   "Logging": {
     "LogLevel": {
@@ -8,9 +9,10 @@
     }
   },
   "AllowedHosts": "*",
-  "AllowedOrigins": [ "http://localhost:4200" ],
+  "AllowedOrigins": [ "http://localhost:4200", "http://172.24.12.39:9090", "https://localhost:8088", "http://localhost:5131", "http://localhost:7192" ],
   "ConnectionStrings": {
-    "Default": "Server=SDD-VMP04-SQL17\\DD_DEVELOP01;Database=DD_ECM;User Id=sa;Password=dd;Encrypt=false;TrustServerCertificate=True;"
+    "Default": "Server=SDD-VMP04-SQL17\\DD_DEVELOP01;Database=DD_ECM;User Id=sa;Password=dd;Encrypt=false;TrustServerCertificate=True;",
+    "DbMigrationTest": "Server=SDD-VMP04-SQL17\\DD_DEVELOP01;Database=DD_ECM_DATA_MIGR_TEST;User Id=sa;Password=dd;Encrypt=false;TrustServerCertificate=True;"
   },
   "DirectorySearchOptions": {
     "ServerName": "DD-VMP01-DC01",
@@ -22,11 +24,11 @@
     }
   },
   "AuthClientParams": {
-    "Url": "https://localhost:7192/auth-hub",
+    "Url": "http://172.24.12.39:9090/auth-hub",
     "PublicKeys": [
       {
         "Issuer": "auth.digitaldata.works",
-        "Audience": "sign-flow-gen.digitaldata.works"
+        "Audience": "sign-flow.digitaldata.works"
       }
     ],
     "RetryDelay": "00:00:05"
@@ -35,7 +37,7 @@
     "Cookie": "AuthToken",
     "QueryString": "AuthToken",
     "Issuer": "auth.digitaldata.works",
-    "Audience": "work-flow.digitaldata.works"
+    "Audience": "sign-flow.digitaldata.works"
   },
   "PSPDFKitLicenseKey": "SXCtGGY9XA-31OGUXQK-r7c6AkdLGPm2ljuyDr1qu0kkhLvydg-Do-fxpNUF4Rq3fS_xAnZRNFRHbXpE6sQ2BMcCSVTcXVJO6tPviexjpiT-HnrDEySlUERJnnvh-tmeOWprxS6BySPnSILkmaVQtUfOIUS-cUbvvEYHTvQBKbSF8di4XHQFyfv49ihr51axm3NVV3AXwh2EiKL5C5XdqBZ4sQ4O7vXBjM2zvxdPxlxdcNYmiU83uAzw7B83O_jubPzya4CdUHh_YH7Nlp2gP56MeG1Sw2JhMtfG3Rj14Sg4ctaeL9p6AEWca5dDjJ2li5tFIV2fQSsw6A_cowLu0gtMm5i8IfJXeIcQbMC2-0wGv1oe9hZYJvFMdzhTM_FiejM0agemxt3lJyzuyP8zbBSOgp7Si6A85krLWPZptyZBTG7pp7IHboUHfPMxCXqi-zMsqewOJtQBE2mjntU-lPryKnssOpMPfswwQX7QSkJYV5EMqNmEhQX6mEkp2wcqFzMC7bJQew1aO4pOpvChUaMvb1vgRek0HxLag0nwQYX2YrYGh7F_xXJs-8HNwJe8H0-eW4x4faayCgM5rB5772CCCsD9ThZcvXFrjNHHLGJ8WuBUFm6LArvSfFQdii_7j-_sqHMpeKZt26NFgivj1A==",
   "Content-Security-Policy": [ // The first format parameter {0} will be replaced by the nonce value.

EnvelopeGenerator.API/yarp.json

@@ -0,0 +1,25 @@
+{
+  "ReverseProxy": {
+    "Routes": {
+      "auth-login": {
+        "ClusterId": "auth-hub",
+        "Match": {
+          "Path": "/api/auth",
+          "Methods": [ "POST" ]
+        },
+        "Transforms": [
+          { "PathSet": "/api/auth/sign-flow" }
+        ]
+      }
+    },
+    "Clusters": {
+      "auth-hub": {
+        "Destinations": {
+          "primary": {
+            "Address": "http://172.24.12.39:9090"
+          }
+        }
+      }
+    }
+  }
+}

EnvelopeGenerator.Application/Common/Configurations/AuthenticatorParams.cs

@@ -0,0 +1,33 @@
+namespace EnvelopeGenerator.Application.Common.Configurations;
+
+/// <summary>
+/// 
+/// </summary>
+public class AuthenticatorParams
+{
+    /// <summary>
+    /// Default value is 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz01234567890123456789012345678901234567890123456789'
+    /// </summary>
+    public string CharPool { get; init; } = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz01234567890123456789012345678901234567890123456789";
+
+    //TODO: Increase the DefaultTotpSecretKeyLength (e.g. to 32) but make sure that the QR code is generated correctly and can be scanned by the authenticator.
+    /// <summary>
+    /// Default value is 20
+    /// </summary>
+    public int DefaultTotpSecretKeyLength { get; init; } = 20;
+
+    /// <summary>
+    /// Default value is 
+    /// </summary>
+    public string TotpIssuer { get; init; } = "signFlow";
+
+    /// <summary>
+    /// 0 is user email, 1 is secret key and 2 is issuer.
+    /// </summary>
+    public string TotpUrlFormat { get; init; } = "otpauth://totp/{0}?secret={1}&issuer={2}";
+
+    /// <summary>
+    /// Default value is 20.
+    /// </summary>
+    public int TotpQRPixelsPerModule { get; init; } = 20;
+}

EnvelopeGenerator.Application/Common/Configurations/DispatcherParams.cs

@@ -0,0 +1,27 @@
+namespace EnvelopeGenerator.Application.Common.Configurations;
+
+/// <summary>
+/// 
+/// </summary>
+public class DispatcherParams
+{
+    /// <summary>
+    /// Default value is 1
+    /// </summary>
+    public int SendingProfile { get; init; } = 1;
+
+    /// <summary>
+    /// Defalt value is 'DDEnvelopGenerator'
+    /// </summary>
+    public string AddedWho { get; init; } = "DDEnvelopGenerator";
+
+    /// <summary>
+    /// Default value is 202377
+    /// </summary>
+    public int ReminderTypeId { get; init; } = 202377;
+
+    /// <summary>
+    /// Default value is string.Empty
+    /// </summary>
+    public string? EmailAttmt1 { get; init; } = null;
+}

EnvelopeGenerator.Application/Common/Configurations/GtxMessagingParams.cs

@@ -1,20 +1,37 @@
-using DigitalData.Core.Abstractions.Client;
-namespace EnvelopeGenerator.Application.Configurations;
+using DigitalData.Core.Client.Interface;
+namespace EnvelopeGenerator.Application.Common.Configurations;
 
 /// <summary>
 /// https://www.gtx-messaging.com/en/api-docs/sms-rest-api/
 /// </summary>
 public class GtxMessagingParams : IHttpClientOptions
 {
+    /// <summary>
+    /// 
+    /// </summary>
     public required string Uri { get; init; }
 
+    /// <summary>
+    /// 
+    /// </summary>
     public string? Path { get; init; }
 
+    /// <summary>
+    /// 
+    /// </summary>
     public Dictionary<string, object>? Headers { get; init; }
 
+    /// <summary>
+    /// 
+    /// </summary>
     public Dictionary<string, object?>? QueryParams { get; init; }
-
+    /// <summary>
+    /// Default value is 'to'
+    /// </summary>
     public string RecipientQueryParamName { get; init; } = "to";
 
+    /// <summary>
+    /// Default value is 'text'
+    /// </summary>
     public string MessageQueryParamName { get; init; } = "text";
 }

EnvelopeGenerator.Application/Common/Configurations/MailParams.cs

@@ -0,0 +1,12 @@
+namespace EnvelopeGenerator.Application.Common.Configurations;
+
+/// <summary>
+/// 
+/// </summary>
+public class MailParams
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public required Dictionary<string, string> Placeholders { get; init; }
+}

EnvelopeGenerator.Application/Common/Configurations/TotpSmsParams.cs

@@ -0,0 +1,81 @@
+using OtpNet;
+using System.Globalization;
+
+namespace EnvelopeGenerator.Application.Common.Configurations;
+
+/// <summary>
+/// 
+/// </summary>
+public class TotpSmsParams
+{
+    /// <summary>
+    /// The unit is second.
+    /// </summary>
+    public int TotpStep { get; init; } = 90;
+
+    /// <summary>
+    /// Default value is 'Ihr 2FA-Passwort lautet {0}. Gültig bis {1}'
+    /// </summary>
+    public string Format { get; init; } = "Ihr 2FA-Passwort lautet {0}. Gültig bis {1}";
+    
+    /// <summary>
+    /// 
+    /// </summary>
+    public ExpirationHandler Expiration { get; init; } = new();
+
+    /// <summary>
+    /// Default value is VerificationWindow.RfcSpecifiedNetworkDelay
+    /// </summary>
+    public VerificationWindow? TotpVerificationWindow { get; private init; } = VerificationWindow.RfcSpecifiedNetworkDelay;
+
+    private IEnumerable<int>? _tvwParams;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public IEnumerable<int>? TotpVerificationWindowParams
+    {
+        get => _tvwParams;
+        init
+        {
+            _tvwParams = value;
+            if(_tvwParams is not null)
+                TotpVerificationWindow = new(previous: _tvwParams.ElementAtOrDefault(0), future: _tvwParams.ElementAtOrDefault(0));
+        }
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public class ExpirationHandler
+    {
+        /// <summary>
+        /// Default value is 'e{0}_r{1}_sms_code_expiration'
+        /// </summary>
+        public string CacheKeyFormat { get; init; } = "e{0}_r{1}_sms_code_expiration";
+
+        /// <summary>
+        /// Default value is HH:mm:ss
+        /// </summary>
+        public string Format { get; init; } = "HH:mm:ss";
+
+        /// <summary>
+        /// Default value is 'de-DE'
+        /// </summary>
+        public string CultureName
+        {
+            get => _cultureInfo.Name;
+            init => _cultureInfo = new(value);
+        }
+
+        /// <summary>
+        /// Default value is 'de-DE'
+        /// </summary>
+        private CultureInfo _cultureInfo = new("de-DE");
+
+        /// <summary>
+        /// Default value is 'de-DE'
+        /// </summary>
+        public CultureInfo CultureInfo => _cultureInfo;
+    }
+}

EnvelopeGenerator.Application/Common/Dto/AnnotationDto.cs

@@ -0,0 +1,73 @@
+namespace EnvelopeGenerator.Application.Common.Dto;
+
+/// <summary>
+/// 
+/// </summary>
+public record AnnotationCreateDto
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public int ElementId { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string Name { get; init; } = null!;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string Value { get; init; } = null!;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string Type { get; init; } = null!;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public double? X { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public double? Y { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public double? Width { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public double? Height { get; init; }
+}
+
+/// <summary>
+/// 
+/// </summary>
+public record AnnotationDto : AnnotationCreateDto
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public long Id { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public DateTime AddedWhen { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public DateTime? ChangedWhen { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? ChangedWho { get; init; }
+}

EnvelopeGenerator.Application/Common/Dto/ConfigDto.cs

@@ -0,0 +1,30 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.Common.Dto;
+
+/// <summary>
+/// Data Transfer Object representing configuration settings.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class ConfigDto
+{
+    /// <summary>
+    /// Gets or sets the sending profile identifier.
+    /// </summary>
+    public int SendingProfile { get; set; }
+
+    /// <summary>
+    /// Gets or sets the signature host URL or name.
+    /// </summary>
+    public required string SignatureHost { get; set; }
+
+    /// <summary>
+    /// Gets or sets the name of the external program.
+    /// </summary>
+    public string? ExternalProgramName { get; set; }
+
+    /// <summary>
+    /// Gets or sets the path where exports will be saved.
+    /// </summary>
+    public string? ExportPath { get; set; }
+}

EnvelopeGenerator.Application/Common/Dto/DocumentDto.cs

@@ -0,0 +1,35 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.Common.Dto;
+
+/// <summary>
+/// Data Transfer Object representing a document within an envelope, including optional binary data and form elements.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class DocumentDto
+{
+    /// <summary>
+    /// Gets or sets the unique identifier of the document.
+    /// </summary>
+    public int Id { get; set; }
+
+    /// <summary>
+    /// Gets or sets the envelope ID to which the document belongs.
+    /// </summary>
+    public int EnvelopeId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the date and time when the document was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the binary data of the document, if available.
+    /// </summary>
+    public byte[]? ByteData { get; set; }
+
+    /// <summary>
+    /// Gets or sets the collection of elements associated with the document for receiver interactions, if any.
+    /// </summary>
+    public IEnumerable<SignatureDto>? Elements { get; set; }
+}

EnvelopeGenerator.Application/Common/Dto/DocumentStatusDto.cs

@@ -0,0 +1,51 @@
+using EnvelopeGenerator.Domain.Constants;
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.Common.Dto;
+
+/// <summary>
+/// Data Transfer Object representing the status of a document for a specific receiver.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class DocumentStatusDto
+{
+    /// <summary>
+    /// Gets or sets the unique identifier of the document status entry.
+    /// </summary>
+    public int Id { get; set; }
+
+    /// <summary>
+    /// Gets or sets the ID of the associated envelope.
+    /// </summary>
+    public int EnvelopeId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the ID of the receiver associated with this status.
+    /// </summary>
+    public int ReceiverId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the current status code.
+    /// </summary>
+    public EnvelopeStatus Status { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when the status was changed.
+    /// </summary>
+    public DateTime? StatusChangedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when this record was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when this record was last changed.
+    /// </summary>
+    public DateTime? ChangedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the display value associated with the status.
+    /// </summary>
+    public string? Value { get; set; }
+}

EnvelopeGenerator.Application/Common/Dto/EmailTemplateDto.cs

@@ -1,13 +1,12 @@
-using DigitalData.Core.Abstractions;
-using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc;
 
-namespace EnvelopeGenerator.Application.DTOs
+namespace EnvelopeGenerator.Application.Common.Dto
 {
     /// <summary>
     /// 
     /// </summary>
     [ApiExplorerSettings(IgnoreApi = true)]
-    public record EmailTemplateDto : IUnique<int>
+    public record EmailTemplateDto
     {
         /// <summary>
         /// 

EnvelopeGenerator.Application/Common/Dto/EnvelopeDto.cs

@@ -0,0 +1,126 @@
+using DigitalData.EmailProfilerDispatcher.Abstraction.Attributes;
+using DigitalData.UserManager.Application.DTOs.User;
+using EnvelopeGenerator.Domain.Constants;
+using EnvelopeGenerator.Domain.Entities;
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.Common.Dto;
+
+/// <summary>
+/// 
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public record EnvelopeDto
+{
+	/// <summary>
+	/// 
+	/// </summary>
+	public int Id { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public int UserId { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public required EnvelopeStatus Status { get; set; }
+
+    /// <summary>
+    /// Default value is string.Empty
+    /// </summary>
+    public string StatusName { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Default value is string.Empty
+    /// </summary>
+    public string Uuid { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Default value is string.Empty
+    /// </summary>
+    [TemplatePlaceholder("[MESSAGE]")]
+    public string Message { get; set; } = string.Empty;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public DateTime? ChangedWhen { get; set; }
+
+    /// <summary>
+    /// Default value is string.Empty
+    /// </summary>
+    [TemplatePlaceholder("[DOCUMENT_TITLE]")]
+    public string Title { get; set; } = string.Empty;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public int? ContractType { get; set; }
+
+    /// <summary>
+    /// Default value is 'de-DE'
+    /// </summary>
+    public string Language { get; set; } = "de-DE";
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public int? EnvelopeTypeId { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public bool ReadOnly => EnvelopeTypeId == 2;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public int? CertificationType { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public bool UseAccessCode { get; set; } = true;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public bool TFAEnabled { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public UserReadDto? User { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public EnvelopeType? EnvelopeType { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? EnvelopeTypeTitle { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public bool IsAlreadySent { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public byte[]? DocResult { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public IEnumerable<DocumentDto>? Documents { get; set; }
+}

EnvelopeGenerator.Application/Common/Dto/EnvelopeReceiver/EnvelopeReceiverDto.cs

@@ -0,0 +1,78 @@
+using DigitalData.EmailProfilerDispatcher.Abstraction.Attributes;
+using EnvelopeGenerator.Application.Common.Dto.Receiver;
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiver;
+
+/// <summary>
+/// 
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public record EnvelopeReceiverDto
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public EnvelopeDto? Envelope { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public ReceiverDto? Receiver { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public (int Envelope, int Receiver) Id => (Envelope: EnvelopeId, Receiver: ReceiverId);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public int EnvelopeId { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public int ReceiverId { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public int Sequence { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    [TemplatePlaceholder("[NAME_RECEIVER]")]
+    public string? Name { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? JobTitle { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? CompanyName { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? PrivateMessage { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public DateTime AddedWhen { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public DateTime? ChangedWhen { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public bool HasPhoneNumber { get; init; }
+}

EnvelopeGenerator.Application/Common/Dto/EnvelopeReceiver/EnvelopeReceiverSecretDto.cs

@@ -0,0 +1,20 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiver;
+
+/// <summary>
+/// 
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public record EnvelopeReceiverSecretDto : EnvelopeReceiverDto
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? AccessCode { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? PhoneNumber { get; init; }
+}

EnvelopeGenerator.Application/Common/Dto/EnvelopeReceiverReadOnly/EnvelopeReceiverReadOnlyCreateDto.cs

@@ -0,0 +1,39 @@
+using Microsoft.AspNetCore.Mvc;
+using System.ComponentModel.DataAnnotations;
+using System.Text.Json.Serialization;
+
+namespace EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiverReadOnly;
+
+/// <summary>
+/// 
+/// </summary>
+/// <param name="DateValid"></param>
+[ApiExplorerSettings(IgnoreApi = true)]
+public record EnvelopeReceiverReadOnlyCreateDto(
+    DateTime DateValid)
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    [EmailAddress]
+    [Required]
+    public required string ReceiverMail { get; init; }
+
+    /// <summary>
+    /// Default value is null
+    /// </summary>
+    [JsonIgnore]
+    public long? EnvelopeId { get; set; } = null;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    [JsonIgnore]
+    public string? AddedWho { get; set; }
+
+    /// <summary>
+    /// Default value is DateTime.Now
+    /// </summary>
+    [JsonIgnore]
+    public DateTime AddedWhen { get; } = DateTime.Now;
+};

EnvelopeGenerator.Application/Common/Dto/EnvelopeReceiverReadOnly/EnvelopeReceiverReadOnlyDto.cs

@@ -0,0 +1,64 @@
+using EnvelopeGenerator.Application.Common.Dto;
+using EnvelopeGenerator.Application.Common.Dto.Receiver;
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiverReadOnly;
+
+/// <summary>
+/// Represents a read-only Data Transfer Object (DTO) for an envelope receiver.
+/// Contains information about the receiver, associated envelope, and audit details.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class EnvelopeReceiverReadOnlyDto
+{
+    /// <summary>
+    /// Gets or inits the unique identifier of the envelope receiver.
+    /// </summary>
+    public long Id { get; init; }
+
+    /// <summary>
+    /// Gets or inits the identifier of the associated envelope.
+    /// </summary>
+    public long EnvelopeId { get; init; }
+
+    /// <summary>
+    /// Gets or inits the email address of the receiver.
+    /// </summary>
+    public required string ReceiverMail { get; set; }
+
+    /// <summary>
+    /// Gets or inits the date until which the receiver is valid.
+    /// </summary>
+    public DateTime DateValid { get; set; }
+
+    /// <summary>
+    /// Gets or inits the date and time when the receiver was added.
+    /// </summary>
+    public DateTime AddedWhen { get; init; }
+
+    /// <summary>
+    /// Gets or inits the user who added the receiver.
+    /// Default value is 'unknown'.
+    /// </summary>
+    public string AddedWho { get; init; } = "Unknown";
+
+    /// <summary>
+    /// Gets or inits the associated envelope details.
+    /// </summary>
+    public EnvelopeDto? Envelope { get; set; }
+
+    /// <summary>
+    /// Gets or inits the user who last changed the receiver, if any.
+    /// </summary>
+    public string? ChangedWho { get; set; }
+
+    /// <summary>
+    /// Gets or inits the date and time when the receiver was last changed, if any.
+    /// </summary>
+    public DateTime? ChangedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or inits the associated receiver details.
+    /// </summary>
+    public ReceiverDto? Receiver { get; set; }
+}

EnvelopeGenerator.Application/Common/Dto/EnvelopeReceiverReadOnly/EnvelopeReceiverReadOnlyUpdateDto.cs

@@ -0,0 +1,31 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiverReadOnly;
+
+/// <summary>
+/// Data Transfer Object for updating a read-only envelope receiver.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class EnvelopeReceiverReadOnlyUpdateDto
+{
+    /// <summary>
+    /// Gets or sets the unique identifier of the envelope receiver.
+    /// </summary>
+    public long Id { get; init; }
+
+    /// <summary>
+    /// Gets or sets the date when the envelope receiver becomes valid.
+    /// </summary>
+    public DateTime DateValid { get; set; }
+
+    /// <summary>
+    /// Gets or sets the name of the user who made the change.
+    /// Default value is unknown.
+    /// </summary>
+    public string ChangedWho { get; set; } = "Unknown";
+
+    /// <summary>
+    /// Gets or sets the date and time when the change was made.
+    /// </summary>
+    public DateTime ChangedWhen { get; set; } = DateTime.Now;
+}

EnvelopeGenerator.Application/Common/Dto/EnvelopeTypeDto.cs

@@ -0,0 +1,85 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.Common.Dto;
+
+/// <summary>
+/// Data Transfer Object representing a type of envelope with its configuration settings.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class EnvelopeTypeDto
+{
+    /// <summary>
+    /// Gets or sets the unique identifier of the envelope type.
+    /// </summary>
+    public int Id { get; set; }
+
+    /// <summary>
+    /// Gets or sets the title of the envelope type.
+    /// </summary>
+    public string Title { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Gets or sets the language code used in this envelope type.
+    /// </summary>
+    public string Language { get; set; } = "de-DE";
+
+    /// <summary>
+    /// Gets or sets the number of days after which the envelope expires.
+    /// </summary>
+    public int? ExpiresDays { get; set; }
+
+    /// <summary>
+    /// Gets or sets the certification type identifier.
+    /// </summary>
+    public int? CertificationType { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether an access code is required.
+    /// </summary>
+    public bool? UseAccessCode { get; set; }
+
+    /// <summary>
+    /// Gets or sets the final email template ID to be sent to the creator.
+    /// </summary>
+    public int? FinalEmailToCreator { get; set; }
+
+    /// <summary>
+    /// Gets or sets the final email template ID to be sent to the receivers.
+    /// </summary>
+    public int? FinalEmailToReceivers { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when this envelope type was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when this envelope type was last changed.
+    /// </summary>
+    public DateTime? ChangedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the number of days before expiry when a warning should be sent.
+    /// </summary>
+    public int? ExpiresWarningDays { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether reminder emails should be sent.
+    /// </summary>
+    public bool? SendReminderEmails { get; set; }
+
+    /// <summary>
+    /// Gets or sets the number of days before the first reminder is sent.
+    /// </summary>
+    public int? FirstReminderDays { get; set; }
+
+    /// <summary>
+    /// Gets or sets the interval in days between reminder emails.
+    /// </summary>
+    public int? ReminderIntervalDays { get; set; }
+
+    /// <summary>
+    /// Gets or sets the contract type associated with the envelope type.
+    /// </summary>
+    public int? ContractType { get; set; }
+}

EnvelopeGenerator.Application/Common/Dto/History/HistoryCreateDto.cs

@@ -0,0 +1,32 @@
+namespace EnvelopeGenerator.Application.Common.Dto.History;
+
+/// <summary>
+/// Data Transfer Object for creating a new envelope history record.
+/// </summary>
+public class HistoryCreateDto
+{
+    /// <summary>
+    /// Gets or sets the identifier of the envelope.
+    /// </summary>
+    public int EnvelopeId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the user reference associated with the action.
+    /// </summary>
+    public required string UserReference { get; set; }
+
+    /// <summary>
+    /// Gets or sets the status of the envelope at the time of the action.
+    /// </summary>
+    public int Status { get; set; }
+
+    /// <summary>
+    /// Gets or sets the date and time when the action occurred.
+    /// </summary>
+    public DateTime? ActionDate { get; set; }
+
+    /// <summary>
+    /// Gets or sets an optional comment related to the action.
+    /// </summary>
+    public string? Comment { get; set; }
+}

EnvelopeGenerator.Application/Common/Dto/History/HistoryDto.cs

@@ -0,0 +1,74 @@
+using DigitalData.UserManager.Application.DTOs.User;
+using EnvelopeGenerator.Application.Common.Dto.Receiver;
+using EnvelopeGenerator.Domain.Constants;
+
+namespace EnvelopeGenerator.Application.Common.Dto.History;
+
+/// <summary>
+/// Data Transfer Object representing the history of an envelope, including status, sender, receiver, and related metadata.
+/// </summary>
+public record HistoryDto
+{
+    /// <summary>
+    /// Unique identifier for the envelope history entry.
+    /// </summary>
+    public long Id { get; set; }
+
+    /// <summary>
+    /// Identifier of the associated envelope.
+    /// </summary>
+    public int EnvelopeId { get; set; }
+
+    /// <summary>
+    /// Reference string for the user related to this history entry.
+    /// </summary>
+    public required string UserReference { get; set; }
+
+    /// <summary>
+    /// Include code of the envelope at this history point.
+    /// </summary>
+    public EnvelopeStatus Status { get; set; }
+
+    /// <summary>
+    /// Type of reference for this history entry.
+    /// </summary>
+    public ReferenceType ReferenceType => ((int)Status).ToString().FirstOrDefault() switch
+    {
+        '1' => ReferenceType.Sender,
+        '2' => ReferenceType.Receiver,
+        _ => ReferenceType.System,
+    };
+
+    /// <summary>
+    /// Human-readable name of the status.
+    /// </summary>
+    public string? StatusName { get; set; }
+
+    /// <summary>
+    /// Date and time when this history entry was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Date and time when an action was performed, if applicable.
+    /// </summary>
+    public DateTime? ActionDate { get; set; }
+
+    /// <summary>
+    /// Information about the sender associated with this history entry.
+    /// </summary>
+    public UserCreateDto? Sender { get; set; }
+
+    /// <summary>
+    /// Information about the receiver associated with this history entry.
+    /// </summary>
+    public ReceiverDto? Receiver { get; set; }
+
+    /// <summary>
+    /// Optional comment related to this history entry.
+    /// </summary>
+    public string? Comment { get; set; }
+
+    /// <inheritdoc/>
+    public override int GetHashCode() => Id.GetHashCode();
+};

EnvelopeGenerator.Application/Common/Dto/MappingProfile.cs

@@ -1,13 +1,13 @@
 using AutoMapper;
-using EnvelopeGenerator.Application.DTOs.EnvelopeHistory;
-using EnvelopeGenerator.Application.DTOs.EnvelopeReceiver;
-using EnvelopeGenerator.Application.DTOs.EnvelopeReceiverReadOnly;
-using EnvelopeGenerator.Application.DTOs.Messaging;
-using EnvelopeGenerator.Application.DTOs.Receiver;
-using EnvelopeGenerator.Application.Extensions;
+using EnvelopeGenerator.Application.Common.Dto.History;
+using EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiver;
+using EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiverReadOnly;
+using EnvelopeGenerator.Application.Common.Dto.Messaging;
+using EnvelopeGenerator.Application.Common.Dto.Receiver;
+using EnvelopeGenerator.Application.Common.Extensions;
 using EnvelopeGenerator.Domain.Entities;
 
-namespace EnvelopeGenerator.Application.DTOs;
+namespace EnvelopeGenerator.Application.Common.Dto;
 
 /// <summary>
 /// Represents the AutoMapper profile configuration for mapping between
@@ -23,42 +23,36 @@ public class MappingProfile : Profile
     {
         // Entity to DTO mappings
         CreateMap<Config, ConfigDto>();
-        CreateMap<DocumentReceiverElement, DocumentReceiverElementDto>();
+        CreateMap<Signature, SignatureDto>();
         CreateMap<DocumentStatus, DocumentStatusDto>();
         CreateMap<EmailTemplate, EmailTemplateDto>();
         CreateMap<Envelope, EnvelopeDto>();
-        CreateMap<EnvelopeCertificate, EnvelopeCertificateDto>();
-        CreateMap<EnvelopeDocument, EnvelopeDocumentDto>();
-        CreateMap<Domain.Entities.EnvelopeHistory, EnvelopeHistoryDto>();
-        CreateMap<Domain.Entities.EnvelopeHistory, EnvelopeHistoryCreateDto>();
+        CreateMap<Document, DocumentDto>();
+        CreateMap<Domain.Entities.History, HistoryDto>();
+        CreateMap<Domain.Entities.History, HistoryCreateDto>();
         CreateMap<Domain.Entities.EnvelopeReceiver, EnvelopeReceiverDto>();
         CreateMap<Domain.Entities.EnvelopeReceiver, EnvelopeReceiverSecretDto>();
         CreateMap<EnvelopeType, EnvelopeTypeDto>();
-        CreateMap<Domain.Entities.Receiver, ReceiverReadDto>();
-        CreateMap<Domain.Entities.Receiver, ReceiverCreateDto>();
-        CreateMap<Domain.Entities.Receiver, ReceiverUpdateDto>();
-        CreateMap<UserReceiver, UserReceiverDto>();
+        CreateMap<Domain.Entities.Receiver, ReceiverDto>();
         CreateMap<Domain.Entities.EnvelopeReceiverReadOnly, EnvelopeReceiverReadOnlyDto>();
+        CreateMap<ElementAnnotation, AnnotationDto>();
 
         // DTO to Entity mappings
         CreateMap<ConfigDto, Config>();
-        CreateMap<DocumentReceiverElementDto, DocumentReceiverElement>();
+        CreateMap<SignatureDto, Signature>();
         CreateMap<DocumentStatusDto, DocumentStatus>();
         CreateMap<EmailTemplateDto, EmailTemplate>();
         CreateMap<EnvelopeDto, Envelope>();
-        CreateMap<EnvelopeCertificateDto, EnvelopeCertificate>();
-        CreateMap<EnvelopeDocumentDto, EnvelopeDocument>();
-        CreateMap<EnvelopeHistoryDto, Domain.Entities.EnvelopeHistory>();
-        CreateMap<EnvelopeHistoryCreateDto, Domain.Entities.EnvelopeHistory>();
+        CreateMap<DocumentDto, Document>();
+        CreateMap<HistoryDto, Domain.Entities.History>();
+        CreateMap<HistoryCreateDto, Domain.Entities.History>();
         CreateMap<EnvelopeReceiverDto, Domain.Entities.EnvelopeReceiver>();
         CreateMap<EnvelopeTypeDto, EnvelopeType>();
-        CreateMap<ReceiverReadDto, Domain.Entities.Receiver>().ForMember(rcv => rcv.EnvelopeReceivers, rcvReadDto => rcvReadDto.Ignore());
-        CreateMap<ReceiverCreateDto, Domain.Entities.Receiver>();
-        CreateMap<ReceiverUpdateDto, Domain.Entities.Receiver>();
-        CreateMap<UserReceiverDto, UserReceiver>();
-        CreateMap<EnvelopeReceiverBase, EnvelopeReceiverBasicDto>();
+        CreateMap<ReceiverDto, Domain.Entities.Receiver>().ForMember(rcv => rcv.EnvelopeReceivers, rcvReadDto => rcvReadDto.Ignore());
         CreateMap<EnvelopeReceiverReadOnlyCreateDto, Domain.Entities.EnvelopeReceiverReadOnly>();
         CreateMap<EnvelopeReceiverReadOnlyUpdateDto, Domain.Entities.EnvelopeReceiverReadOnly>();
+        CreateMap<AnnotationCreateDto, ElementAnnotation>()
+            .ForMember(dest => dest.AddedWhen, opt => opt.MapFrom(_ => DateTime.UtcNow));
 
         // Messaging mappings
         // for GTX messaging

EnvelopeGenerator.Application/Common/Dto/Messaging/GtxMessagingResponse.cs

@@ -0,0 +1,9 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.Common.Dto.Messaging;
+
+/// <summary>
+/// 
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class GtxMessagingResponse : Dictionary<string, object?> { }

EnvelopeGenerator.Application/Common/Dto/Messaging/SmsResponse.cs

@@ -0,0 +1,25 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.Common.Dto.Messaging;
+
+/// <summary>
+/// 
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public record SmsResponse
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public required bool Ok { get; init; }
+
+    /// <summary>
+    /// Returns !Ok
+    /// </summary>
+    public bool Failed => !Ok;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public dynamic? Errors { get; init; }
+}

EnvelopeGenerator.Application/Common/Dto/Receiver/ReceiverDto.cs

@@ -0,0 +1,63 @@
+using EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiver;
+using Microsoft.AspNetCore.Mvc;
+using System.Text.Json.Serialization;
+
+namespace EnvelopeGenerator.Application.Common.Dto.Receiver;
+
+/// <summary>
+/// 
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class ReceiverDto
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public int Id { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public required string EmailAddress { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public required string Signature { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    [JsonIgnore]
+    public string? TotpSecretkey { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    [JsonIgnore]
+    public IEnumerable<EnvelopeReceiverDto>? EnvelopeReceivers { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? LastUsedName => EnvelopeReceivers?.LastOrDefault()?.Name;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public DateTime? TfaRegDeadline { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    public override int GetHashCode()
+    {
+        return Id.GetHashCode();
+    }
+}

EnvelopeGenerator.Application/Common/Dto/SignatureDto.cs

@@ -0,0 +1,96 @@
+using EnvelopeGenerator.Domain.Interfaces;
+using Microsoft.AspNetCore.Mvc;
+
+namespace EnvelopeGenerator.Application.Common.Dto;
+
+/// <summary>
+/// Data Transfer Object representing a positioned element assigned to a document receiver.
+/// </summary>
+[ApiExplorerSettings(IgnoreApi = true)]
+public class SignatureDto : ISignature
+{
+    /// <summary>
+    /// Gets or sets the unique identifier of the element.
+    /// </summary>
+    public int Id { get; set; }
+
+    /// <summary>
+    /// Gets or sets the identifier of the associated document.
+    /// </summary>
+    public int DocumentId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the identifier of the receiver.
+    /// </summary>
+    public int ReceiverId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the type of the element.
+    /// </summary>
+    public int ElementType { get; set; }
+
+    /// <summary>
+    /// Gets or sets the X coordinate of the element.
+    /// </summary>
+    public double X { get; set; }
+
+    /// <summary>
+    /// Gets or sets the Y coordinate of the element.
+    /// </summary>
+    public double Y { get; set; }
+
+    /// <summary>
+    /// Gets or sets the width of the element.
+    /// </summary>
+    public double Width { get; set; }
+
+    /// <summary>
+    /// Gets or sets the height of the element.
+    /// </summary>
+    public double Height { get; set; }
+
+    /// <summary>
+    /// Gets or sets the page number where the element appears.
+    /// </summary>
+    public int Page { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether the element is required.
+    /// </summary>
+    public bool Required { get; set; }
+
+    /// <summary>
+    /// Gets or sets the tooltip text for the element.
+    /// </summary>
+    public string? Tooltip { get; set; }
+
+    /// <summary>
+    /// Gets or sets a value indicating whether the element is read-only.
+    /// </summary>
+    public bool ReadOnly { get; set; }
+
+    /// <summary>
+    /// Gets or sets the annotation index for ordering or reference.
+    /// </summary>
+    public int AnnotationIndex { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when the element was added.
+    /// </summary>
+    public DateTime AddedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timestamp when the element was last changed, if applicable.
+    /// </summary>
+    public DateTime? ChangedWhen { get; set; }
+
+    /// <summary>
+    /// Gets or sets the top position of the element (in layout terms).
+    /// </summary>
+    public double Top => Y;
+
+    /// <summary>
+    /// Gets or sets the left position of the element (in layout terms).
+    /// </summary>
+    public double Left => X;
+}

EnvelopeGenerator.Application/Common/EnvelopeFlag.cs

@@ -0,0 +1,27 @@
+namespace EnvelopeGenerator.Application.Common;
+
+/// <summary>
+/// 
+/// </summary>
+public enum EnvelopeFlag
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    EnvelopeOrReceiverNonexists,
+
+    /// <summary>
+    /// 
+    /// </summary>
+    NonDecodableEnvelopeReceiverId,
+
+    /// <summary>
+    /// 
+    /// </summary>
+    WrongEnvelopeReceiverId,
+
+    /// <summary>
+    /// 
+    /// </summary>
+    AccessCodeNull
+}

EnvelopeGenerator.Application/Common/Extensions/CacheExtensions.cs

@@ -0,0 +1,222 @@
+using Microsoft.Extensions.Caching.Distributed;
+
+namespace EnvelopeGenerator.Application.Common.Extensions;
+
+/// <summary>
+/// 
+/// </summary>
+public static class CacheExtensions
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="value"></param>
+    /// <param name="options"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static Task SetLongAsync(this IDistributedCache cache, string key, long value, DistributedCacheEntryOptions? options = null, CancellationToken cToken = default)
+        => options is null
+            ? cache.SetAsync(key, BitConverter.GetBytes(value), token: cToken)
+            : cache.SetAsync(key, BitConverter.GetBytes(value), options: options, token: cToken);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static async Task<long?> GetLongAsync(this IDistributedCache cache, string key, CancellationToken cToken = default)
+    {
+        var value = await cache.GetAsync(key, cToken);
+        return value is null ? null : BitConverter.ToInt64(value, 0);
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="value"></param>
+    /// <param name="options"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static Task SetDateTimeAsync(this IDistributedCache cache, string key, DateTime value, DistributedCacheEntryOptions? options = null, CancellationToken cToken = default)
+        => cache.SetLongAsync(key: key, value: value.Ticks, options: options, cToken: cToken);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static async Task<DateTime?> GetDateTimeAsync(this IDistributedCache cache, string key, CancellationToken cToken = default)
+    {
+        var value = await cache.GetAsync(key, cToken);
+        return value is null ? null : new(BitConverter.ToInt64(value, 0));
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="value"></param>
+    /// <param name="options"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static Task SetTimeSpanAsync(this IDistributedCache cache, string key, TimeSpan value, DistributedCacheEntryOptions? options = null, CancellationToken cToken = default)
+        => cache.SetLongAsync(key: key, value: value.Ticks, options: options, cToken);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static async Task<TimeSpan?> GetTimeSpanAsync(this IDistributedCache cache, string key, CancellationToken cToken = default)
+    {
+        var value = await cache.GetAsync(key, cToken);
+        return value is null ? null : new(BitConverter.ToInt64(value, 0));
+    }
+
+    //TODO: use code generator
+    #region GetOrSetAsync
+
+    #region string
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="factory"></param>
+    /// <param name="options"></param>
+    /// <param name="cacheInBackground"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static async Task<string> GetOrSetAsync(this IDistributedCache cache, string key, Func<string> factory, DistributedCacheEntryOptions? options = null, bool cacheInBackground = false, CancellationToken cToken = default)
+    {
+        var value = await cache.GetStringAsync(key, cToken);
+        if (value is null)
+        {
+            // create new and save
+            value = factory();
+
+            Task CacheAsync() => options is null
+                    ? cache.SetStringAsync(key, value, cToken)
+                    : cache.SetStringAsync(key, value, options, cToken);
+
+            if (cacheInBackground)
+                _ = Task.Run(async () => await CacheAsync(), cToken);
+            else
+                await CacheAsync();
+        }
+
+        return value;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="factoryAsync"></param>
+    /// <param name="options"></param>
+    /// <param name="cacheInBackground"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static async Task<string> GetOrSetAsync(this IDistributedCache cache, string key, Func<Task<string>> factoryAsync, DistributedCacheEntryOptions? options = null, bool cacheInBackground = false, CancellationToken cToken = default)
+    {
+        var value = await cache.GetStringAsync(key, cToken);
+        if(value is null)
+        {
+            // create new and save
+            value = await factoryAsync();
+
+            Task CacheAsync() => options is null
+                ? cache.SetStringAsync(key: key, value: value, token: cToken)
+                : cache.SetStringAsync(key: key, value: value, options: options, token: cToken);
+
+            if (cacheInBackground)
+                _ = Task.Run(async () => await CacheAsync(), cToken);
+            else
+                await CacheAsync();
+        }
+
+        return value;
+    }
+    #endregion
+
+    #region DateTime
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="factory"></param>
+    /// <param name="options"></param>
+    /// <param name="cacheInBackground"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static async Task<DateTime> GetOrSetAsync(this IDistributedCache cache, string key, Func<DateTime> factory, DistributedCacheEntryOptions? options = null, bool cacheInBackground = false, CancellationToken cToken = default)
+    {
+        if (await cache.GetDateTimeAsync(key, cToken) is DateTime dateTimeValue)
+            return dateTimeValue;
+        else
+        {
+            // create new and save
+            var newValue = factory();
+
+            Task CacheAsync() => options is null
+                    ? cache.SetDateTimeAsync(key, newValue, cToken: cToken)
+                    : cache.SetDateTimeAsync(key, newValue, options, cToken);
+
+            if (cacheInBackground)
+                _ = Task.Run(async () => await CacheAsync(), cToken);
+            else
+                await CacheAsync();
+
+            return newValue;
+        }
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="cache"></param>
+    /// <param name="key"></param>
+    /// <param name="factory"></param>
+    /// <param name="options"></param>
+    /// <param name="cacheInBackground"></param>
+    /// <param name="cToken"></param>
+    /// <returns></returns>
+    public static async Task<DateTime> GetOrSetAsync(this IDistributedCache cache, string key, Func<Task<DateTime>> factory, DistributedCacheEntryOptions? options = null, bool cacheInBackground = false, CancellationToken cToken = default)
+    {
+        if (await cache.GetDateTimeAsync(key, cToken) is DateTime dateTimeValue)
+            return dateTimeValue;
+        else
+        {
+            // create new and save
+            var newValue = await factory();
+
+            Task CacheAsync() => options is null
+                    ? cache.SetDateTimeAsync(key, newValue, cToken: cToken)
+                    : cache.SetDateTimeAsync(key, newValue, options, cToken);
+
+            if (cacheInBackground)
+                _ = Task.Run(async () => await CacheAsync(), cToken);
+            else
+                await CacheAsync();
+
+            return newValue;
+        }
+    }
+    #endregion
+
+    #endregion
+}

EnvelopeGenerator.Application/Common/Extensions/DecodingExtensions.cs

@@ -0,0 +1,182 @@
+using EnvelopeGenerator.Domain.Constants;
+using System.Text;
+
+namespace EnvelopeGenerator.Application.Common.Extensions;
+
+/// <summary>
+/// 
+/// </summary>
+public static class DecodingExtensions
+{
+    /// <summary>
+    /// Validates whether a given string is a correctly formatted Base-64 encoded string.
+    /// </summary>
+    /// <remarks>
+    /// This method checks the string for proper Base-64 formatting, which includes validating
+    /// the length of the string (must be divisible by 4). It also checks each character to ensure
+    /// it belongs to the Base-64 character set (A-Z, a-z, 0-9, '+', '/', and '=' for padding).
+    /// The method ensures that padding characters ('=') only appear at the end of the string and
+    /// are in a valid configuration (either one '=' at the end if the string's length % 4 is 3,
+    /// or two '==' if the length % 4 is 2).
+    /// </remarks>
+    /// <param name="input">The Base-64 encoded string to validate.</param>
+    /// <returns>
+    /// <c>true</c> if the string is a valid Base-64 encoded string; otherwise, <c>false</c>.
+    /// </returns>
+    /// <example>
+    /// <code>
+    /// string testString = "TWFuIGlzIGRpc3Rpbmd1aXNoZWQsIG5vdCBvbmx5IGJ5IGhpcyByZWFzb24sIGJ1dCBieSB0aGlzIHNpbmd1bGFyIHBhc3Npb24gZnJvbSBvdGhlciBhbmltYWxzLCB3aGljaCBpcyBhIGx1c3Qgb2YgdGhlIG1pbmQsIHRoYXQgYnk=";
+    /// bool isValid = IsValidBase64String(testString);
+    /// Console.WriteLine(isValid); // Output: true
+    /// </code>
+    /// </example>
+    public static bool IsBase64String(this string input)
+    {
+        // Check if the string is null or empty
+        if (string.IsNullOrEmpty(input))
+        {
+            return false;
+        }
+
+        // Replace valid base-64 padding
+        input = input.Trim();
+        int mod4 = input.Length % 4;
+        if (mod4 > 0)
+        {
+            // Base-64 string lengths should be divisible by 4
+            return false;
+        }
+
+        // Check each character to ensure it is valid base-64
+        foreach (char c in input)
+        {
+            if (!char.IsLetterOrDigit(c) && c != '+' && c != '/' && c != '=')
+            {
+                // Invalid character detected
+                return false;
+            }
+        }
+
+        // Ensure no invalid padding scenarios exist
+        if (input.EndsWith("==") && input.Length % 4 == 0 ||
+            input.EndsWith("=") && input.Length % 4 == 3)
+        {
+            return true;
+        }
+
+        return input.IndexOf('=') == -1; // No padding allowed except at the end
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="encodedKey"></param>
+    /// <param name="decodedKeys"></param>
+    /// <returns></returns>
+    public static bool TryDecode(this string encodedKey, out string[] decodedKeys)
+    {
+        try
+        {
+            byte[] bytes = Convert.FromBase64String(encodedKey);
+            string decodedString = Encoding.UTF8.GetString(bytes);
+            decodedKeys = decodedString.Split(new string[] { "::" }, StringSplitOptions.None);
+            return true;
+        }
+        catch(ArgumentNullException) { }
+        catch (FormatException) { }
+        catch(ArgumentException) { }
+
+        decodedKeys = Array.Empty<string>();
+        return false;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="decodedKeys"></param>
+    /// <returns></returns>
+    public static EncodeType GetEncodeType(this string[] decodedKeys) => decodedKeys.Length switch
+    {
+        2 => EncodeType.EnvelopeReceiver,
+        3 => long.TryParse(decodedKeys[1], out var _) ? EncodeType.EnvelopeReceiverReadOnly : EncodeType.Undefined,
+        _ => EncodeType.Undefined,
+    };
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="decodedKeys"></param>
+    /// <returns></returns>
+    /// <exception cref="InvalidOperationException"></exception>
+    public static (string? EnvelopeUuid, string? ReceiverSignature) ParseEnvelopeReceiverId(this string[] decodedKeys)
+        => decodedKeys.GetEncodeType() == EncodeType.EnvelopeReceiver
+        ? (EnvelopeUuid: decodedKeys[0], ReceiverSignature: decodedKeys[1])
+        : throw new InvalidOperationException("Attempted to convert a decoded other than type EnvelopeReceiver to EnvelopeReceiver.");
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="decodedKeys"></param>
+    /// <returns></returns>
+    /// <exception cref="InvalidOperationException"></exception>
+    public static long ParseReadOnlyId(this string[] decodedKeys)
+        => decodedKeys.GetEncodeType() == EncodeType.EnvelopeReceiverReadOnly
+        ? long.Parse(decodedKeys[1])
+        : throw new InvalidOperationException("Attempted to convert a decoded other than type EnvelopeReceiver to EnvelopeReceiver. ");
+
+    /// <summary>
+    /// Decodes the envelope receiver ID and extracts the envelope UUID and receiver signature.
+    /// </summary>
+    /// <param name="envelopeReceiverId">The base64 encoded string containing the envelope UUID and receiver signature.</param>
+    /// <returns>A tuple containing the envelope UUID and receiver signature.</returns>
+    public static (string? EnvelopeUuid, string? ReceiverSignature) DecodeEnvelopeReceiverId(this string envelopeReceiverId)
+    {
+        if (!envelopeReceiverId.IsBase64String())
+        {
+            return (null, null);
+        }
+        byte[] bytes = Convert.FromBase64String(envelopeReceiverId);
+        string decodedString = Encoding.UTF8.GetString(bytes);
+        string[] parts = decodedString.Split(new string[] { "::" }, StringSplitOptions.None);
+
+        if (parts.Length > 1)
+            return (EnvelopeUuid: parts[0], ReceiverSignature: parts[1]);
+        else
+            return (string.Empty, string.Empty);
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeReceiverReadOnlyId"></param>
+    /// <returns></returns>
+    public static long? DecodeEnvelopeReceiverReadOnlyId(this string envelopeReceiverReadOnlyId)
+    {
+        if (!envelopeReceiverReadOnlyId.IsBase64String())
+        {
+            return null;
+        }
+        byte[] bytes = Convert.FromBase64String(envelopeReceiverReadOnlyId);
+        string decodedString = Encoding.UTF8.GetString(bytes);
+        string[] parts = decodedString.Split(new string[] { "::" }, StringSplitOptions.None);
+
+        if (parts.Length > 2)
+            return long.TryParse(parts[1], out long readOnlyId) ? readOnlyId : null;
+        else
+            return null;
+    }
+
+    /// <summary>
+    /// Gets the envelope UUID from the decoded envelope receiver ID.
+    /// </summary>
+    /// <param name="envelopeReceiverId">The base64 encoded string to decode.</param>
+    /// <returns>The envelope UUID.</returns>
+    public static string? GetEnvelopeUuid(this string envelopeReceiverId) => envelopeReceiverId.DecodeEnvelopeReceiverId().EnvelopeUuid;
+
+    /// <summary>
+    /// Gets the receiver signature from the decoded envelope receiver ID.
+    /// </summary>
+    /// <param name="envelopeReceiverId">The base64 encoded string to decode.</param>
+    /// <returns>The receiver signature.</returns>
+    public static string? GetReceiverSignature(this string envelopeReceiverId) => envelopeReceiverId.DecodeEnvelopeReceiverId().ReceiverSignature;
+}

EnvelopeGenerator.Application/Common/Extensions/EncodingExtensions.cs

@@ -0,0 +1,38 @@
+using System.Text;
+
+namespace EnvelopeGenerator.Application.Common.Extensions;
+
+/// <summary>
+/// Provides extension methods for decoding and extracting information from an envelope receiver ID.
+/// </summary>
+public static class EncodingExtensions
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="readOnlyId"></param>
+    /// <returns></returns>
+    public static string ToEnvelopeKey(this long readOnlyId)
+    {
+        //The random number is used as a salt to increase security but it is not saved in the database.
+        string combinedString = $"{Random.Shared.Next()}::{readOnlyId}::{Random.Shared.Next()}";
+        byte[] bytes = Encoding.UTF8.GetBytes(combinedString);
+        string base64String = Convert.ToBase64String(bytes);
+
+        return base64String;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="input"></param>
+    /// <returns></returns>
+    public static string ToEnvelopeKey(this (string envelopeUuid, string receiverSignature) input)
+    {
+        string combinedString = $"{input.envelopeUuid}::{input.receiverSignature}";
+        byte[] bytes = Encoding.UTF8.GetBytes(combinedString);
+        string base64String = Convert.ToBase64String(bytes);
+
+        return base64String;
+    }
+}

EnvelopeGenerator.Application/Common/Extensions/JsonExtensions.cs

@@ -0,0 +1,18 @@
+using System.Text.Json;
+
+namespace EnvelopeGenerator.Application.Common.Extensions;
+
+/// <summary>
+/// 
+/// </summary>
+public static class JsonExtensions
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="obj"></param>
+    /// <param name="options"></param>
+    /// <returns></returns>
+    public static string ToJson(this object obj, JsonSerializerOptions? options = null)
+        => JsonSerializer.Serialize(obj, options);
+}

EnvelopeGenerator.Application/Common/Extensions/LoggerExtensions.cs

@@ -1,10 +1,21 @@
 using Microsoft.Extensions.Logging;
 using System.Text;
 
-namespace EnvelopeGenerator.Extensions
+namespace EnvelopeGenerator.Application.Common.Extensions
 {
+    /// <summary>
+    /// 
+    /// </summary>
     public static class LoggerExtensions
     {
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="logger"></param>
+        /// <param name="envelopeReceiverId"></param>
+        /// <param name="exception"></param>
+        /// <param name="message"></param>
+        /// <param name="args"></param>
         public static void LogEnvelopeError(this ILogger logger, string envelopeReceiverId, Exception? exception = null, string? message = null, params object?[] args)
         {
             var sb = new StringBuilder().AppendLine(envelopeReceiverId.DecodeEnvelopeReceiverId().ToTitle());
@@ -18,6 +29,15 @@ namespace EnvelopeGenerator.Extensions
                 logger.Log(LogLevel.Error, exception, sb.AppendLine(exception.Message).ToString(), args);
         }
 
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="logger"></param>
+        /// <param name="uuid"></param>
+        /// <param name="signature"></param>
+        /// <param name="exception"></param>
+        /// <param name="message"></param>
+        /// <param name="args"></param>
         public static void LogEnvelopeError(this ILogger logger, string? uuid, string? signature = null, Exception? exception = null, string? message = null, params object?[] args)
         {
             var sb = new StringBuilder($"Envelope Uuid: {uuid}");
@@ -34,6 +54,11 @@ namespace EnvelopeGenerator.Extensions
                 logger.Log(LogLevel.Error, exception, sb.ToString(), args);
         }
 
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="envelopeReceiverTuple"></param>
+        /// <returns></returns>
         public static string ToTitle(this (string? UUID, string? Signature) envelopeReceiverTuple)
         {
             return $"UUID is {envelopeReceiverTuple.UUID} and signature is {envelopeReceiverTuple.Signature}";

EnvelopeGenerator.Application/Common/Extensions/MappingExtensions.cs

@@ -0,0 +1,27 @@
+using EnvelopeGenerator.Application.Common.Dto.Messaging;
+
+namespace EnvelopeGenerator.Application.Common.Extensions;
+
+/// <summary>
+/// Provides extension methods for common mapping and conversion operations.
+/// </summary>
+public static class MappingExtensions
+{
+    /// <summary>
+    /// Determines whether the response indicates a successful "OK" message status.
+    /// </summary>
+    /// <param name="gtxMessagingResponse">The response object to evaluate.</param>
+    /// <returns><see langword="true"/> if the response contains a "message-status" key with a value of "ok"  (case-insensitive);
+    /// otherwise, <see langword="false"/>.</returns>
+    public static bool Ok(this GtxMessagingResponse gtxMessagingResponse)
+        => gtxMessagingResponse.TryGetValue("message-status", out var status)
+        && status?.ToString()?.ToLower() == "ok";
+
+    /// <summary>
+    /// Converts the specified byte array to its equivalent string representation encoded in base-64.
+    /// </summary>
+    /// <param name="bytes">The byte array to encode.</param>
+    /// <returns>A base-64 encoded string representation of the input byte array.</returns>
+    public static string ToBase64String(this byte[] bytes)
+        => Convert.ToBase64String(bytes);
+}

EnvelopeGenerator.Application/Common/Extensions/MemoryCacheExtensions.cs

@@ -1,11 +1,24 @@
-using Microsoft.Extensions.Caching.Memory;
+using EnvelopeGenerator.Application.Common.Extensions;
+using Microsoft.Extensions.Caching.Memory;
 
-namespace EnvelopeGenerator.Extensions;
+namespace EnvelopeGenerator.Application.Common.Extensions;
 
+/// <summary>
+/// 
+/// </summary>
 public static class MemoryCacheExtensions
 {
     private static readonly Guid BaseId = Guid.NewGuid();
 
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <typeparam name="TEnum"></typeparam>
+    /// <param name="memoryCache"></param>
+    /// <param name="key"></param>
+    /// <param name="ignores"></param>
+    /// <returns></returns>
+    /// <exception cref="InvalidOperationException"></exception>
     public static IDictionary<string, int> GetEnumAsDictionary<TEnum>(this IMemoryCache memoryCache, string key = "", params object[] ignores)
         where TEnum : Enum
         => memoryCache.GetOrCreate(BaseId + typeof(TEnum).FullName + key, _ =>

EnvelopeGenerator.Application/Common/Extensions/QueryExtensions.cs

@@ -0,0 +1,125 @@
+using DigitalData.Core.Exceptions;
+using EnvelopeGenerator.Application.Common.Extensions;
+using EnvelopeGenerator.Application.Common.Query;
+using EnvelopeGenerator.Domain.Entities;
+using EnvelopeGenerator.Domain.Interfaces;
+
+namespace EnvelopeGenerator.Application.Common.Extensions;
+
+/// <summary>
+/// 
+/// </summary>
+public static class QueryExtensions
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <typeparam name="TEntity"></typeparam>
+    /// <param name="root"></param>
+    /// <param name="query"></param>
+    /// <param name="notnull"></param>
+    /// <returns></returns>
+    /// <exception cref="BadRequestException"></exception>
+    public static IQueryable<TEntity> Where<TEntity>(this IQueryable<TEntity> root, EnvelopeQueryBase query, bool notnull = true)
+        where TEntity : IHasEnvelope
+    {
+        if (query.Id is not null)
+            root = root.Where(e => e.Envelope!.Id == query.Id);
+        else if (query.Uuid is not null)
+            root = root.Where(e => e.Envelope!.Uuid == query.Uuid);
+        else if (notnull)
+            throw new BadRequestException(
+                "Either Envelope Id or Envelope Uuid must be provided in the query."
+            );
+
+        return root;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="root"></param>
+    /// <param name="query"></param>
+    /// <param name="notnull"></param>
+    /// <returns></returns>
+    /// <exception cref="BadRequestException"></exception>
+    public static IQueryable<Envelope> Where(this IQueryable<Envelope> root, EnvelopeQueryBase query, bool notnull = true)
+    {
+        if (query.Id is not null)
+            root = root.Where(e => e.Id == query.Id);
+        else if (query.Uuid is not null)
+            root = root.Where(e => e.Uuid == query.Uuid);
+        else if (notnull)
+            throw new BadRequestException(
+                "Either Envelope Id or Envelope Uuid must be provided in the query."
+            );
+
+        return root;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <typeparam name="TEntity"></typeparam>
+    /// <param name="root"></param>
+    /// <param name="query"></param>
+    /// <param name="notnull"></param>
+    /// <returns></returns>
+    /// <exception cref="BadRequestException"></exception>
+    public static IQueryable<TEntity> Where<TEntity>(this IQueryable<TEntity> root, ReceiverQueryBase query, bool notnull = true)
+        where TEntity : IHasReceiver
+    {
+        if (query.Id is not null)
+            root = root.Where(e => e.Receiver!.Id == query.Id);
+        else if (query.EmailAddress is not null)
+            root = root.Where(e => e.Receiver!.EmailAddress == query.EmailAddress);
+        else if (query.Signature is not null)
+            root = root.Where(e => e.Receiver!.Signature == query.Signature);
+        else if (notnull)
+            throw new BadRequestException(
+                "Receiver must have at least one identifier (Id, EmailAddress, or Signature)."
+            );
+
+        return root;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="root"></param>
+    /// <param name="query"></param>
+    /// <param name="notnull"></param>
+    /// <returns></returns>
+    /// <exception cref="BadRequestException"></exception>
+    public static IQueryable<Receiver> Where(this IQueryable<Receiver> root, ReceiverQueryBase query, bool notnull = true)
+    {
+        if (query.Id is not null)
+            root = root.Where(e => e.Id == query.Id);
+        else if (query.EmailAddress is not null)
+            root = root.Where(e => e.EmailAddress == query.EmailAddress);
+        else if (query.Signature is not null)
+            root = root.Where(e => e.Signature == query.Signature);
+        else if (notnull)
+            throw new BadRequestException(
+                "Receiver must have at least one identifier (Id, EmailAddress, or Signature)."
+            );
+
+        return root;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <typeparam name="TEntity"></typeparam>
+    /// <typeparam name="TEnvelopeQuery"></typeparam>
+    /// <typeparam name="TReceiverQuery"></typeparam>
+    /// <param name="root"></param>
+    /// <param name="query"></param>
+    /// <param name="notnull"></param>
+    /// <returns></returns>
+    public static IQueryable<TEntity> Where<TEntity, TEnvelopeQuery, TReceiverQuery>(this IQueryable<TEntity> root, EnvelopeReceiverQueryBase<TEnvelopeQuery, TReceiverQuery> query, bool notnull = true)
+        where TEntity : IHasEnvelope, IHasReceiver
+        where TEnvelopeQuery : EnvelopeQueryBase, new()
+        where TReceiverQuery : ReceiverQueryBase, new() 
+        => root.Where(query.Envelope, notnull).Where(query.Receiver, notnull);
+}

EnvelopeGenerator.Application/Common/Extensions/StringExtension.cs

@@ -0,0 +1,30 @@
+using OtpNet;
+
+namespace EnvelopeGenerator.Application.Common.Extensions;
+
+/// <summary>
+/// 
+/// </summary>
+public static class StringExtension
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="totp"></param>
+    /// <param name="secret"></param>
+    /// <returns></returns>
+    public static bool IsValidTotp(this string totp, string secret)
+    {
+        var secret_bytes = Base32Encoding.ToBytes(secret);
+        var secret_totp = new Totp(secret_bytes);
+        return secret_totp.VerifyTotp(totp, out _, VerificationWindow.RfcSpecifiedNetworkDelay);
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="seperator"></param>
+    /// <param name="values"></param>
+    /// <returns></returns>
+    public static string Join(this IEnumerable<string> values, string seperator) => string.Join(seperator, values);
+}

EnvelopeGenerator.Application/Common/Extensions/TaskExtensions.cs

@@ -0,0 +1,105 @@
+using DigitalData.Core.Exceptions;
+
+namespace EnvelopeGenerator.Application.Common.Extensions;
+
+/// <summary>
+/// Extension methods for tasks
+/// </summary>
+[Obsolete("Implement Mediator behaviors in the Osolete .NET project.")]
+public static class TaskExtensions
+{
+    /// <summary>
+    /// Awaits the specified task and ensures that the result is not <c>null</c>.
+    /// If the result is <c>null</c>, the exception created by factory-method is thrown.
+    /// </summary>
+    /// <typeparam name="T">The type of the result.</typeparam>
+    /// <typeparam name="TException">The type of the exception.</typeparam>
+    /// <param name="task">The task to await.</param>
+    /// <param name="factory">Exception provider</param>
+    /// <returns>The awaited result if not <c>null</c>.</returns>
+    /// <exception>Thrown if the result is <c>null</c>.</exception>
+    [Obsolete("Implement Mediator behaviors in the Osolete .NET project.")]
+    public static async Task<T> ThrowIfNull<T, TException>(this Task<T?> task, Func<TException> factory) where TException : Exception
+    {
+        var result = await task;
+        return result ?? throw factory();
+    }
+
+    /// <summary>
+    /// Awaits the specified task and ensures that the result is not <c>empty</c>.
+    /// If the result contains no elements, the exception created by factory-method is thrown.
+    /// </summary>
+    /// <typeparam name="T">The element type of the collection.</typeparam>
+    /// <typeparam name="TException">The type of the exception.</typeparam>
+    /// <param name="task">The task to await.</param>
+    /// <param name="factory">Exception provider</param>
+    /// <returns>The awaited collection if it is not <c>null</c> or empty.</returns>
+    /// <exception cref="NotFoundException">Thrown if the result is <c>null</c> or empty.</exception>
+    [Obsolete("Implement Mediator behaviors in the Osolete .NET project.")]
+    public static async Task<IEnumerable<T>> ThrowIfEmpty<T, TException>(this Task<IEnumerable<T>> task, Func<TException> factory) where TException : Exception
+    {
+        var result = await task;
+        return result?.Any() ?? false ? result : throw factory();
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+    /// <typeparam name="I"></typeparam>
+    /// <param name="task"></param>
+    /// <param name="act"></param>
+    /// <returns></returns>
+    [Obsolete("Implement Mediator behaviors in the Osolete .NET project.")]
+    public static async Task<I> Then<T, I>(this Task<T> task, Func<T, I> act)
+    {
+        var res = await task;
+        return act(res);
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+    /// <param name="task"></param>
+    /// <returns></returns>
+    [Obsolete("Implement Mediator behaviors in the Osolete .NET project.")]
+    public static Task<T?> FirstOrDefaultAsync<T>(this Task<IEnumerable<T>> task) => task.Then(t => t.FirstOrDefault());
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+    /// <typeparam name="TException"></typeparam>
+    /// <param name="task"></param>
+    /// <param name="factory"></param>
+    /// <returns></returns>
+    public static Task<T> FirstAsync<T, TException>(this Task<IEnumerable<T>> task, Func<TException> factory) 
+        where TException : Exception 
+        => task.Then(t => t.FirstOrDefault() ?? throw factory());
+}
+
+/// <summary>
+/// 
+/// </summary>
+public static class Exceptions
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public static NotFoundException NotFound() => new();
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    [Obsolete("Implement Mediator behaviors in the Osolete .NET project.")]
+    public static BadRequestException BadRequest() => new();
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    [Obsolete("Implement Mediator behaviors in the Osolete .NET project.")]
+    public static ForbiddenException Forbidden() => new();
+}

EnvelopeGenerator.Application/Common/Extensions/XSSExtensions.cs

@@ -0,0 +1,43 @@
+using Ganss.Xss;
+using Microsoft.Extensions.Localization;
+using System.Text.Encodings.Web;
+
+namespace EnvelopeGenerator.Application.Common.Extensions;
+
+/// <summary>
+/// 
+/// </summary>
+public static class XSSExtensions
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="value"></param>
+    /// <param name="encoder"></param>
+    /// <returns></returns>
+    public static string? TryEncode(this string? value, UrlEncoder encoder) => value is null ? value : encoder.Encode(value);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="value"></param>
+    /// <param name="encoder"></param>
+    /// <returns></returns>
+    public static string? TryEncode(this LocalizedString? value, UrlEncoder encoder) => value is null ? null : encoder.Encode(value);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="html"></param>
+    /// <param name="sanitizer"></param>
+    /// <returns></returns>
+    public static string? TrySanitize(this string? html, HtmlSanitizer sanitizer) => html is null ? html : sanitizer.Sanitize(html);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="html"></param>
+    /// <param name="sanitizer"></param>
+    /// <returns></returns>
+    public static string? TrySanitize(this LocalizedString? html, HtmlSanitizer sanitizer) => html is null ? null : sanitizer.Sanitize(html);
+}

EnvelopeGenerator.Application/Common/Interfaces/Repositories/IConfigRepository.cs

@@ -0,0 +1,17 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Common.Interfaces.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IConfigRepository : ICRUDRepository<Config, int>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    Task<Config?> ReadFirstAsync();
+}

EnvelopeGenerator.Application/Common/Interfaces/Repositories/IDocumentReceiverElementRepository.cs

@@ -0,0 +1,11 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Common.Interfaces.Repositories;
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IDocumentReceiverElementRepository : ICRUDRepository<Signature, int>
+{
+}

EnvelopeGenerator.Application/Common/Interfaces/Repositories/IDocumentStatusRepository.cs

@@ -0,0 +1,12 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Common.Interfaces.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IDocumentStatusRepository : ICRUDRepository<DocumentStatus, int>
+{
+}

EnvelopeGenerator.Application/Common/Interfaces/Repositories/IEmailTemplateRepository.cs

@@ -0,0 +1,19 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Constants;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Common.Interfaces.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IEmailTemplateRepository : ICRUDRepository<EmailTemplate, int>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="type"></param>
+    /// <returns></returns>
+    Task<EmailTemplate?> ReadByNameAsync(EmailTemplateType type);
+}

EnvelopeGenerator.Application/Common/Interfaces/Repositories/IEnvelopeDocumentRepository.cs

@@ -0,0 +1,12 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Common.Interfaces.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IEnvelopeDocumentRepository : ICRUDRepository<Document, int>
+{
+}

EnvelopeGenerator.Application/Common/Interfaces/Repositories/IEnvelopeHistoryRepository.cs

@@ -0,0 +1,32 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Constants;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Common.Interfaces.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IEnvelopeHistoryRepository : ICRUDRepository<History, long>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="userReference"></param>
+    /// <param name="status"></param>
+    /// <returns></returns>
+    Task<int> CountAsync(int? envelopeId = null, string? userReference = null, EnvelopeStatus? status = null);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="userReference"></param>
+    /// <param name="status"></param>
+    /// <param name="withSender"></param>
+    /// <param name="withReceiver"></param>
+    /// <returns></returns>
+    Task<IEnumerable<History>> ReadAsync(int? envelopeId = null, string? userReference = null, EnvelopeStatus? status = null, bool withSender = false, bool withReceiver = false);
+}

EnvelopeGenerator.Application/Common/Interfaces/Repositories/IEnvelopeReceiverReadOnlyRepository.cs

@@ -0,0 +1,12 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Common.Interfaces.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IEnvelopeReceiverReadOnlyRepository : ICRUDRepository<EnvelopeReceiverReadOnly, long>
+{
+}

EnvelopeGenerator.Application/Common/Interfaces/Repositories/IEnvelopeReceiverRepository.cs

@@ -0,0 +1,98 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Application.Envelopes.Queries;
+using EnvelopeGenerator.Domain.Constants;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Common.Interfaces.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IEnvelopeReceiverRepository : ICRUDRepository<EnvelopeReceiver, (int Envelope, int Receiver)>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="withEnvelope"></param>
+    /// <param name="withReceiver"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<IEnumerable<EnvelopeReceiver>> ReadByUuidAsync(string uuid, bool withEnvelope = true, bool withReceiver = false, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="signature"></param>
+    /// <param name="withEnvelope"></param>
+    /// <param name="withReceiver"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<IEnumerable<EnvelopeReceiver>> ReadBySignatureAsync(string signature, bool withEnvelope = false, bool withReceiver = true, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="signature"></param>
+    /// <param name="withEnvelope"></param>
+    /// <param name="withReceiver"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<EnvelopeReceiver?> ReadByUuidSignatureAsync(string uuid, string signature, bool withEnvelope = true, bool withReceiver = true, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="signature"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<string?> ReadAccessCodeAsync(string uuid, string signature, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="signature"></param>
+    /// <returns></returns>
+    Task<int> CountAsync(string uuid, string signature);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="receiverId"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<EnvelopeReceiver?> ReadByIdAsync(int envelopeId, int receiverId, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="envelopeId"></param>
+    /// <param name="receiverId"></param>
+    /// <param name="readOnly"></param>
+    /// <returns></returns>
+    Task<string?> ReadAccessCodeByIdAsync(int envelopeId, int receiverId, bool readOnly = true);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="username"></param>
+    /// <param name="min_status"></param>
+    /// <param name="max_status"></param>
+    /// <param name="ignore_statuses"></param>
+    /// <returns></returns>
+    Task<IEnumerable<EnvelopeReceiver>> ReadByUsernameAsync(string username, EnvelopeStatus? min_status = null, EnvelopeStatus? max_status = null, params EnvelopeStatus[] ignore_statuses);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="email"></param>
+    /// <param name="id"></param>
+    /// <param name="signature"></param>
+    /// <returns></returns>
+    Task<EnvelopeReceiver?> ReadLastByReceiverAsync(string? email = null, int? id = null, string? signature = null);
+}

EnvelopeGenerator.Application/Common/Interfaces/Repositories/IEnvelopeRepository.cs

@@ -0,0 +1,43 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Constants;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Common.Interfaces.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IEnvelopeRepository : ICRUDRepository<Envelope, int>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="documents"></param>
+    /// <param name="history"></param>
+    /// <param name="documentReceiverElement"></param>
+    /// <returns></returns>
+    Task<IEnumerable<Envelope>> ReadAllWithAsync(bool documents = false, bool history = false, bool documentReceiverElement = false);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="uuid"></param>
+    /// <param name="withDocuments"></param>
+    /// <param name="withHistory"></param>
+    /// <param name="withDocumentReceiverElement"></param>
+    /// <param name="withUser"></param>
+    /// <param name="withAll"></param>
+    /// <returns></returns>
+    Task<Envelope?> ReadByUuidAsync(string uuid, bool withDocuments = false, bool withHistory = false, bool withDocumentReceiverElement = false, bool withUser = false, bool withAll = false);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="userId"></param>
+    /// <param name="min_status"></param>
+    /// <param name="max_status"></param>
+    /// <param name="ignore_statuses"></param>
+    /// <returns></returns>
+    Task<IEnumerable<Envelope>> ReadByUserAsync(int userId, EnvelopeStatus? min_status = null, EnvelopeStatus? max_status = null, params EnvelopeStatus[] ignore_statuses);
+}

EnvelopeGenerator.Application/Common/Interfaces/Repositories/IEnvelopeTypeRepository.cs

@@ -0,0 +1,12 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Common.Interfaces.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IEnvelopeTypeRepository : ICRUDRepository<EnvelopeType, int>
+{
+}

EnvelopeGenerator.Application/Common/Interfaces/Repositories/IReceiverRepository.cs

@@ -0,0 +1,19 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Common.Interfaces.Repositories;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use IRepository")]
+public interface IReceiverRepository : ICRUDRepository<Receiver, int>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="emailAddress"></param>
+    /// <param name="signature"></param>
+    /// <returns></returns>
+    Task<Receiver?> ReadByAsync(string? emailAddress = null, string? signature = null);
+}

EnvelopeGenerator.Application/Common/Interfaces/SQLExecutor/IDocumentExecutor.cs

@@ -1,6 +1,6 @@
 using EnvelopeGenerator.Domain.Entities;
 
-namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+namespace EnvelopeGenerator.Application.Common.Interfaces.SQLExecutor;
 
 /// <summary>
 /// 
@@ -14,5 +14,5 @@ public interface IDocumentExecutor
     /// <param name="envelope_uuid"></param>
     /// <param name="cancellation"></param>
     /// <returns></returns>
-    Task<EnvelopeDocument> CreateDocumentAsync(string base64, string envelope_uuid, CancellationToken cancellation = default);
+    Task<Document> CreateDocumentAsync(string base64, string envelope_uuid, CancellationToken cancellation = default);
 }

EnvelopeGenerator.Application/Common/Interfaces/SQLExecutor/IEnvelopeExecutor.cs

@@ -1,7 +1,7 @@
 using Dapper;
 using EnvelopeGenerator.Domain.Entities;
 
-namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+namespace EnvelopeGenerator.Application.Common.Interfaces.SQLExecutor;
 
 /// <summary>
 /// 

EnvelopeGenerator.Application/Common/Interfaces/SQLExecutor/IEnvelopeReceiverExecutor.cs

@@ -1,6 +1,6 @@
 using EnvelopeGenerator.Domain.Entities;
 
-namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+namespace EnvelopeGenerator.Application.Common.Interfaces.SQLExecutor;
 
 /// <summary>
 /// 

EnvelopeGenerator.Application/Common/Interfaces/SQLExecutor/IQuery.cs

@@ -1,4 +1,4 @@
-namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+namespace EnvelopeGenerator.Application.Common.Interfaces.SQLExecutor;
 
 /// <summary>
 /// Provides methods for executing common queries on a given entity type.

EnvelopeGenerator.Application/Common/Interfaces/SQLExecutor/ISQL.cs

@@ -1,4 +1,4 @@
-namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+namespace EnvelopeGenerator.Application.Common.Interfaces.SQLExecutor;
 
 /// <summary>
 /// Represents a raw SQL query contract.

EnvelopeGenerator.Application/Common/Interfaces/SQLExecutor/ISQLExecutor.cs

@@ -1,4 +1,4 @@
-namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+namespace EnvelopeGenerator.Application.Common.Interfaces.SQLExecutor;
 
 /// <summary>
 /// Defines methods for executing raw SQL queries or custom SQL query classes and returning query executors for further operations.

EnvelopeGenerator.Application/Common/Interfaces/SQLExecutor/ISQLExecutorBaseEntity.cs

@@ -1,6 +1,6 @@
 using Dapper;
 
-namespace EnvelopeGenerator.Application.Contracts.SQLExecutor;
+namespace EnvelopeGenerator.Application.Common.Interfaces.SQLExecutor;
 
 /// <summary>
 /// 

EnvelopeGenerator.Application/Common/Interfaces/Services/IAuthenticator.cs

@@ -0,0 +1,63 @@
+using OtpNet;
+
+namespace EnvelopeGenerator.Application.Common.Interfaces.Services;
+
+/// <summary>
+/// 
+/// </summary>
+public interface IAuthenticator
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="length"></param>
+    /// <returns></returns>
+    string GenerateCode(int length);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="length"></param>
+    /// <returns></returns>
+    string GenerateTotpSecretKey(int? length = null);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="userEmail"></param>
+    /// <param name="secretKey"></param>
+    /// <param name="issuer"></param>
+    /// <param name="totpUrlFormat"></param>
+    /// <param name="pixelsPerModule"></param>
+    /// <returns></returns>
+    byte[] GenerateTotpQrCode(string userEmail, string secretKey, string? issuer = null, string? totpUrlFormat = null, int? pixelsPerModule = null);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="userEmail"></param>
+    /// <param name="length"></param>
+    /// <param name="issuer"></param>
+    /// <param name="totpUrlFormat"></param>
+    /// <param name="pixelsPerModule"></param>
+    /// <returns></returns>
+    byte[] GenerateTotpQrCode(string userEmail, int? length = null, string? issuer = null, string? totpUrlFormat = null, int? pixelsPerModule = null);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="secretKey"></param>
+    /// <param name="step"></param>
+    /// <returns></returns>
+    string GenerateTotp(string secretKey, int step = 30);
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="totpCode"></param>
+    /// <param name="secretKey"></param>
+    /// <param name="step"></param>
+    /// <param name="window"></param>
+    /// <returns></returns>
+    bool VerifyTotp(string totpCode, string secretKey, int step = 30, VerificationWindow? window = null);
+}

EnvelopeGenerator.Application/Common/Interfaces/Services/IConfigService.cs

@@ -0,0 +1,31 @@
+using DigitalData.Core.Abstraction.Application;
+using DigitalData.Core.Abstraction.Application.DTO;
+using EnvelopeGenerator.Application.Common.Dto;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Common.Interfaces.Services;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use MediatR")]
+public interface IConfigService : IReadService<ConfigDto, Config, int>
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    Task<DataResult<ConfigDto>> ReadFirstAsync();
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    Task<ConfigDto> ReadDefaultAsync();
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    Task<string> ReadDefaultSignatureHost();
+}

EnvelopeGenerator.Application/Common/Interfaces/Services/IDocumentReceiverElementService.cs

@@ -0,0 +1,13 @@
+using DigitalData.Core.Abstraction.Application;
+using EnvelopeGenerator.Application.Common.Dto;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.Common.Interfaces.Services;
+
+/// <summary>
+/// 
+/// </summary>
+[Obsolete("Use MediatR")]
+public interface IDocumentReceiverElementService : IBasicCRUDService<SignatureDto, Signature, int>
+{
+}