Add SaveSignatureBehavior and resolve merge conflicts

Introduced the `SaveSignatureBehavior` class as a pipeline behavior for handling `SigningCommand` requests. Added necessary `using` directives to include required namespaces. Resolved merge conflicts in `using` directives between `net8.0` and `net9.0` project versions. Implemented the `Handle` method to delegate request processing.

COPILOT_CONTEXT_EN.md

@@ -935,6 +935,229 @@ canvas {
 
 ---
 
+## Signature Caching System — Session 15
+
+**Purpose:** Persist receiver signature across page refreshes using distributed cache (Redis/SQL Server).
+
+### Architecture
+
+**API Cache Controller (`EnvelopeGenerator.API/Controllers/CacheController.cs`):**
+```csharp
+[Route("api/[controller]")]
+[Authorize(Policy = AuthPolicy.Receiver)]
+public class CacheController(IDistributedCache cache, IOptions<CacheOptions> cacheOptions) : ControllerBase
+{
+    private const string SignatureCacheKeyPrefix = "signature:91751687-8ae6-4777-bf5f-b8846085e62e:";
+    
+    [HttpPost("SignatureCapture/{envelopeKey}")]
+    public async Task<IActionResult> SaveSignature(string envelopeKey, 
+        [FromBody] SignatureCaptureDto request, CancellationToken cancel)
+    
+    [HttpGet("SignatureCapture/{envelopeKey}")]
+    public async Task<IActionResult> GetSignature(string envelopeKey, CancellationToken cancel)
+    
+    [HttpDelete("SignatureCapture/{envelopeKey}")]
+    public async Task<IActionResult> DeleteSignature(string envelopeKey, CancellationToken cancel)
+}
+```
+
+**Cache Options (`EnvelopeGenerator.API/Options/CacheOptions.cs`):**
+```csharp
+public sealed class CacheOptions
+{
+    public const string SectionName = "Cache";
+    
+    // If null, signatures never expire (until manual delete)
+    public TimeSpan? SignatureCacheExpiration { get; set; }
+}
+```
+
+**Configuration (appsettings.json):**
+```json
+{
+  "Cache": {
+    "SignatureCacheExpiration": null  // Or "02:00:00" for 2 hours
+  }
+}
+```
+
+**Blazor Service (`EnvelopeGenerator.ReceiverUI/Services/SignatureCacheService.cs`):**
+```csharp
+public class SignatureCacheService(HttpClient http, IOptions<ApiOptions> apiOptions)
+{
+    public async Task SaveSignatureAsync(string envelopeKey, 
+        SignatureCaptureDto signature, CancellationToken cancel = default)
+    
+    public async Task<SignatureCaptureDto?> GetSignatureAsync(string envelopeKey, 
+        CancellationToken cancel = default)
+    
+    public async Task DeleteSignatureAsync(string envelopeKey, 
+        CancellationToken cancel = default)
+}
+```
+
+### Workflow
+
+**1. Page Load (First Time):**
+```csharp
+protected override async Task OnInitializedAsync() {
+    // Try to load cached signature first
+    try {
+        var cachedSignature = await SignatureCacheService.GetSignatureAsync(EnvelopeKey);
+        if (cachedSignature is not null) {
+            _capturedSignature = cachedSignature;
+            _signerFullName = cachedSignature.FullName;
+            _signerPosition = cachedSignature.Position;
+            _signaturePlace = cachedSignature.Place;
+            _signaturePopupVisible = false;  // Skip popup
+        } else {
+            // No cache - show popup
+            _signaturePopupVisible = true;
+        }
+    } catch (Exception ex) {
+        logger.LogWarning(ex, "Failed to load cached signature, showing popup");
+        _signaturePopupVisible = true;  // Fallback to popup
+    }
+}
+```
+
+**2. Save Signature:**
+```csharp
+async Task SaveSignatureAsync() {
+    // ... validation ...
+    
+    _capturedSignature = new SignatureCaptureDto { ... };
+    _signaturePopupVisible = false;
+    
+    // Save to cache (fire-and-forget, ignore errors)
+    _ = Task.Run(async () => {
+        try {
+            await SignatureCacheService.SaveSignatureAsync(EnvelopeKey, _capturedSignature);
+        } catch {
+            // Ignore cache errors
+        }
+    });
+}
+```
+
+**3. Change Signature (Toolbar Button):**
+```csharp
+void OpenSignaturePopup() {
+    _activeSignatureTab = SignatureTabDraw;
+    _signaturePopupVisible = true;
+    
+    // Load current signature into form fields
+    if (_capturedSignature is not null) {
+        _signerFullName = _capturedSignature.FullName;
+        _signerPosition = _capturedSignature.Position;
+        _signaturePlace = _capturedSignature.Place;
+    }
+}
+
+async Task OnPopupShownAsync() {
+    await InitializeActiveSignatureTabAsync();
+    
+    // Load existing signature image to canvas (Draw tab)
+    if (_capturedSignature is not null && _activeSignatureTab == SignatureTabDraw) {
+        await Task.Delay(100);
+        await JSRuntime.InvokeVoidAsync("receiverSignature.loadExistingSignature", 
+            DrawCanvasId, _capturedSignature.DataUrl);
+    }
+}
+```
+
+**JavaScript Helper:**
+```javascript
+receiverSignature.loadExistingSignature(canvasId, dataUrl) {
+    const canvas = document.getElementById(canvasId);
+    const ctx = canvas.getContext('2d');
+    const img = new Image();
+    
+    img.onload = () => {
+        ctx.clearRect(0, 0, canvas.width, canvas.height);
+        ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
+        state.hasSignature = true;
+    };
+    
+    img.src = dataUrl;
+}
+```
+
+**4. Restart Signing (Reset Button):**
+```csharp
+void RestartSigning() {
+    Navigation.NavigateTo(Navigation.Uri, forceLoad: true);
+    // Page reload ? cache cleared ? popup shows
+}
+```
+
+### Toolbar Button Design
+
+**Change Signature Button:**
+```html
+<button class="pdf-toolbar__btn @(_capturedSignature is not null ? "pdf-toolbar__btn--success" : "")" 
+        @onclick="OpenSignaturePopup" 
+        title="@(_capturedSignature is not null ? "Unterschrift ändern" : "Unterschrift erstellen")">
+    @if (_capturedSignature is not null) {
+        <svg>?</svg>  <!-- Checkmark icon -->
+    } else {
+        <svg>??</svg>  <!-- Pen icon -->
+    }
+</button>
+```
+
+**CSS:**
+```css
+.pdf-toolbar__btn--success {
+    background: linear-gradient(135deg, rgba(16, 185, 129, 0.1) 0%, rgba(5, 150, 105, 0.1) 100%);
+    border-color: rgba(16, 185, 129, 0.3);
+    color: #059669;
+}
+
+.pdf-toolbar__btn--success:hover:not(:disabled) {
+    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
+    color: white;
+}
+```
+
+**States:**
+- **No Signature:** Blue button with pen icon
+- **Signature Created:** Green button with checkmark icon
+- **Hover:** Filled green gradient with white icon
+
+### Cache Key Format
+```
+signature:91751687-8ae6-4777-bf5f-b8846085e62e:{envelopeKey}
+```
+- Prefix prevents collisions with other cache keys
+- GUID ensures uniqueness across application instances
+- `envelopeKey` is user-provided identifier (URL parameter)
+
+### Error Handling Philosophy
+
+**API Controller:** No validation, no try-catch, no logging
+- Throws exceptions directly to caller
+- Blazor handles errors with try-catch
+
+**Blazor Service:** No try-catch
+- Throws `HttpRequestException` with status code + body
+- Component catches and handles
+
+**Blazor Component:** Try-catch with fallback
+- Graceful degradation: show popup on cache failure
+- Fire-and-forget saves: ignore errors
+
+### Benefits
+
+1. **UX:** No need to re-enter signature on page refresh
+2. **Performance:** Fast cache retrieval (Redis/SQL)
+3. **Security:** Per-receiver isolation (cookie-based auth)
+4. **Flexibility:** Configurable expiration time
+5. **Reliability:** Graceful degradation on cache failure
+
+---
+
+
 
 
 

EnvelopeGenerator.API/Controllers/AnnotationController.cs

@@ -5,7 +5,7 @@ using EnvelopeGenerator.Application.Common.Dto;
 using EnvelopeGenerator.Application.Common.Extensions;
 using EnvelopeGenerator.Application.Common.Interfaces.Services;
 using EnvelopeGenerator.Application.Common.Notifications.DocSigned;
-using EnvelopeGenerator.Application.Documents.Queries;
+using EnvelopeGenerator.Application.Common.Notifications.RemoveSignature;
 using EnvelopeGenerator.Application.EnvelopeReceivers.Queries;
 using EnvelopeGenerator.Application.Histories.Queries;
 using EnvelopeGenerator.Domain.Constants;
@@ -13,7 +13,6 @@ using MediatR;
 using Microsoft.AspNetCore.Authentication;
 using Microsoft.AspNetCore.Authentication.Cookies;
 using Microsoft.AspNetCore.Authorization;
-using Microsoft.AspNetCore.Components.Forms;
 using Microsoft.AspNetCore.Mvc;
 
 namespace EnvelopeGenerator.API.Controllers;
@@ -62,8 +61,8 @@ public class AnnotationController : ControllerBase
     [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 signature = User.ReceiverSignature();
-        var uuid = User.GetEnvelopeUuidOfReceiver();
+        var uuid = User.EnvelopeUuid();
 
         var envelopeReceiver = await _mediator.ReadEnvelopeReceiverAsync(uuid, signature, cancel).ThrowIfNull(Exceptions.NotFound);
 
@@ -75,12 +74,24 @@ public class AnnotationController : ControllerBase
         else if (await _mediator.AnyHistoryAsync(uuid, new[] { EnvelopeStatus.EnvelopeRejected, EnvelopeStatus.DocumentRejected }, cancel))
             return Problem(statusCode: StatusCodes.Status423Locked);
 
-        var docSignedNotification = await _mediator
+        var envelopeReceiverDto = await _mediator.ReadEnvelopeReceiverAsync(uuid, signature, cancel);
-            .ReadEnvelopeReceiverAsync(uuid, signature, cancel)
+        var docSignedNotification = envelopeReceiverDto is not null
-            .ToDocSignedNotification(psPdfKitAnnotation)
+            ? new DocSignedNotification { EnvelopeReceiver = envelopeReceiverDto, PsPdfKitAnnotation = psPdfKitAnnotation }
-            ?? throw new NotFoundException("Envelope receiver is not found.");
+            : throw new NotFoundException("Envelope receiver is not found.");
 
-        await _mediator.PublishSafely(docSignedNotification, cancel);
+        try
+        {
+            await _mediator.Publish(docSignedNotification, cancel);
+        }
+        catch (Exception)
+        {
+            await _mediator.Publish(new RemoveSignatureNotification()
+            {
+                EnvelopeId = docSignedNotification.EnvelopeReceiver.EnvelopeId,
+                ReceiverId = docSignedNotification.EnvelopeReceiver.ReceiverId
+            }, cancel);
+            throw;
+        }
         await HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
 
         return Ok();
@@ -95,9 +106,9 @@ public class AnnotationController : ControllerBase
     [Obsolete("Use MediatR")]
     public async Task<IActionResult> Reject([FromBody] string? reason = null)
     {
-        var signature = User.GetReceiverSignatureOfReceiver();
+        var signature = User.ReceiverSignature();
-        var uuid = User.GetEnvelopeUuidOfReceiver();
+        var uuid = User.EnvelopeUuid();
-        var mail = User.GetReceiverMailOfReceiver();
+        var mail = User.ReceiverMail();
 
         var envRcvRes = await _envelopeReceiverService.ReadByUuidSignatureAsync(uuid: uuid, signature: signature);
 

EnvelopeGenerator.API/Controllers/CacheController.cs

@@ -0,0 +1,84 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Caching.Distributed;
+using Microsoft.Extensions.Options;
+using System.Text.Json;
+using EnvelopeGenerator.API.Options;
+using EnvelopeGenerator.Domain.Constants;
+using EnvelopeGenerator.API.Extensions;
+
+namespace EnvelopeGenerator.API.Controllers;
+
+/// <summary>
+/// Manages cached data for receivers using distributed cache.
+/// </summary>
+[ApiController]
+[Route("api/[controller]")]
+[Authorize(Policy = AuthPolicy.Receiver)]
+public class CacheController(
+    IDistributedCache cache,
+    IOptions<CacheOptions> cacheOptions) : ControllerBase
+{
+    private const string SignatureCacheKeyPrefix = "envelope-generator.receiver-ui.signature:";
+
+    /// <summary>
+    /// Stores a receiver's signature in cache for the specified envelope.
+    /// </summary>
+    [Authorize(Policy = AuthPolicy.Receiver)]
+    [HttpPost("SignatureCapture/{envelopeKey}")]
+    public async Task<IActionResult> SaveSignature(
+        [FromRoute] string envelopeKey,
+        [FromBody] SignatureCacheRequest request,
+        CancellationToken cancel)
+    {
+        var cacheKey = $"{SignatureCacheKeyPrefix}{User.ReceiverSignature()}";
+        var json = JsonSerializer.Serialize(request);
+        
+        var options = cacheOptions.Value.SignatureCacheExpiration.HasValue
+            ? new DistributedCacheEntryOptions { AbsoluteExpirationRelativeToNow = cacheOptions.Value.SignatureCacheExpiration.Value }
+            : null;
+
+        await cache.SetStringAsync(cacheKey, json, options ?? new DistributedCacheEntryOptions(), cancel);
+
+        return Ok();
+    }
+
+    /// <summary>
+    /// Retrieves a cached signature for the specified envelope.
+    /// </summary>
+    [Authorize(Policy = AuthPolicy.Receiver)]
+    [HttpGet("SignatureCapture/{envelopeKey}")]
+    public async Task<IActionResult> GetSignature([FromRoute] string envelopeKey, CancellationToken cancel)
+    {
+        var cacheKey = $"{SignatureCacheKeyPrefix}{User.ReceiverSignature()}";
+        var json = await cache.GetStringAsync(cacheKey, cancel);
+
+        if (json is null)
+            return NotFound();
+
+        var signature = JsonSerializer.Deserialize<SignatureCacheRequest>(json);
+        return Ok(signature);
+    }
+
+    /// <summary>
+    /// Deletes a cached signature for the specified envelope.
+    /// </summary>
+    [Authorize(Policy = AuthPolicy.Receiver)]
+    [HttpDelete("SignatureCapture/{envelopeKey}")]
+    public async Task<IActionResult> DeleteSignature([FromRoute] string envelopeKey, CancellationToken cancel)
+    {
+        var cacheKey = $"{SignatureCacheKeyPrefix}{User.ReceiverSignature()}";
+        await cache.RemoveAsync(cacheKey, cancel);
+
+        return Ok();
+    }
+}
+
+/// <summary>
+/// Request model for caching signature data.
+/// </summary>
+public sealed record SignatureCacheRequest(
+    string DataUrl,
+    string FullName,
+    string Place,
+    string? Position = null);

EnvelopeGenerator.API/Controllers/DocumentController.cs

@@ -51,7 +51,7 @@ public class DocumentController(IMediator mediator, IAuthorizationService authSe
             if (query is not null)
                 return BadRequest("Query parameters are not allowed for receiver role.");
 
-            var envelopeId = User.GetEnvelopeIdOfReceiver();
+            var envelopeId = User.EnvelopeId();
             var receiverDoc = await mediator.Send(new ReadDocumentQuery { EnvelopeId = envelopeId }, cancel);
             return receiverDoc.ByteData is byte[] receiverDocByte
                 ? File(receiverDocByte, "application/octet-stream")
@@ -71,7 +71,7 @@ public class DocumentController(IMediator mediator, IAuthorizationService authSe
     [HttpGet("{envelopeKey}")]
     public async Task<IActionResult> GetDocumentOfReceiver(string envelopeKey, CancellationToken cancel)
     {
-        int envelopeId = User.GetEnvelopeIdOfReceiver();
+        int envelopeId = User.EnvelopeId();
 
         var senderDoc = await mediator.Send(new ReadDocumentQuery() { EnvelopeId = envelopeId }, cancel);
 

EnvelopeGenerator.API/Controllers/EnvelopeReceiverController.cs

@@ -200,7 +200,7 @@ 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 ?? Enumerable.Empty<Application.EnvelopeReceivers.Commands.Signature>())
+            foreach (var sign in request.Receivers.Where(r => r.EmailAddress == rcv.EmailAddress).FirstOrDefault()?.DocReceiverElements ?? Enumerable.Empty<Application.EnvelopeReceivers.Commands.DocReceiverElementCreateDto>())
             {
                 using SqlConnection conn = new(_cnnStr);
                 conn.Open();

EnvelopeGenerator.API/Controllers/ReadOnlyController.cs

@@ -41,14 +41,14 @@ public class ReadOnlyController : ControllerBase
     [Obsolete("Use MediatR")]
     public async Task<IActionResult> CreateAsync([FromBody] EnvelopeReceiverReadOnlyCreateDto createDto)
     {
-        var authReceiverMail = User.GetReceiverMailOfReceiver();
+        var authReceiverMail = User.ReceiverMail();
         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();
+        var envelopeId = User.EnvelopeId();
 
         createDto.AddedWho = authReceiverMail;
         createDto.EnvelopeId = envelopeId;

EnvelopeGenerator.API/Controllers/SignatureController.cs

@@ -36,15 +36,15 @@ public class SignatureController : ControllerBase
     /// <returns></returns>
     [Authorize(Policy = AuthPolicy.Receiver)]
     [HttpGet("{envelopeKey}")]
-    public async Task<IActionResult> GetAnnotsOfReceiver(string envelopeKey, CancellationToken cancel)
+    public async Task<IActionResult> Get(string envelopeKey, CancellationToken cancel)
     {
-        int envelopeId = User.GetEnvelopeIdOfReceiver();
+        int envelopeId = User.EnvelopeId();
 
-        int receiverId = User.GetReceiverIdOfReceiver();
+        int receiverId = User.ReceiverId();
 
         var doc = await _mediator.Send(new ReadDocumentQuery() { EnvelopeId = envelopeId }, cancel);
 
-        if (doc.Elements is not IEnumerable<SignatureDto> docSignatures)
+        if (doc.Elements is not IEnumerable<DocReceiverElementDto> docSignatures)
             return NotFound("Document is empty.");
 
         var rcvSignatures = docSignatures.Where(s => s.ReceiverId == receiverId).ToList();

EnvelopeGenerator.API/EnvelopeClaimTypes.cs

@@ -1,17 +0,0 @@
-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

@@ -34,6 +34,7 @@
     <PackageReference Include="DigitalData.Auth.Client" Version="1.3.7" />
     <PackageReference Include="DigitalData.Core.API" Version="2.2.1" />
     <PackageReference Include="HtmlSanitizer" Version="9.0.892" />
+    <PackageReference Include="Microsoft.Extensions.Caching.SqlServer" Version="8.0.11" Condition="'$(TargetFramework)' == 'net8.0'" />
     <PackageReference Include="itext" Version="8.0.5" />
     <PackageReference Include="itext.bouncy-castle-adapter" Version="8.0.5" />
     <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="9.0.4" Condition="'$(TargetFramework)' == 'net9.0'" />

EnvelopeGenerator.API/Extensions/ReceiverClaimExtensions.cs

@@ -1,8 +1,6 @@
-using System.Linq;
+using DigitalData.Auth.Claims;
+using Microsoft.IdentityModel.JsonWebTokens;
 using System.Security.Claims;
-using EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiver;
-using Microsoft.AspNetCore.Authentication;
-using Microsoft.AspNetCore.Authentication.Cookies;
 
 namespace EnvelopeGenerator.API.Extensions;
 
@@ -11,12 +9,14 @@ namespace EnvelopeGenerator.API.Extensions;
 /// </summary>
 public static class ReceiverClaimExtensions
 {
-    private static readonly string[] EnvelopeIdClaimTypes = [EnvelopeClaimTypes.Id, "envelope_id", "EnvelopeId"];
+    /// <summary>
-    private static readonly string[] ReceiverIdClaimTypes = ["receiver_id", "ReceiverId"];
+    /// 
-    private static readonly string[] EnvelopeUuidClaimTypes = [ClaimTypes.NameIdentifier, "envelope_uuid", "EnvelopeUuid"];
+    /// </summary>
-    private static readonly string[] ReceiverSignatureClaimTypes = [ClaimTypes.Hash, "receiver_sig", "ReceiverSignature"];
+    /// <param name="user"></param>
-
+    /// <param name="claimType"></param>
-    private static string GetRequiredClaimOfReceiver(this ClaimsPrincipal user, string claimType)
+    /// <returns></returns>
+    /// <exception cref="InvalidOperationException"></exception>
+    private static string GetRequiredClaimValue(this ClaimsPrincipal user, string claimType)
     {
         var value = user.FindFirstValue(claimType);
         if (value is not null)
@@ -32,7 +32,7 @@ public static class ReceiverClaimExtensions
         throw new InvalidOperationException(message);
     }
 
-    private static string GetRequiredClaimOfReceiver(this ClaimsPrincipal user, params string[] claimTypes)
+    private static string GetRequiredClaimValue(this ClaimsPrincipal user, params string[] claimTypes)
     {
         foreach (var claimType in claimTypes.Where(t => !string.IsNullOrWhiteSpace(t)).Distinct())
         {
@@ -52,89 +52,45 @@ public static class ReceiverClaimExtensions
     /// <summary>
     /// Gets the authenticated envelope UUID from the claims.
     /// </summary>
-    public static string GetEnvelopeUuidOfReceiver(this ClaimsPrincipal user) => user.GetRequiredClaimOfReceiver(EnvelopeUuidClaimTypes);
+    public static string EnvelopeUuid(this ClaimsPrincipal user)
+        => user.GetRequiredClaimValue(EnvelopeClaimNames.EnvelopeUuid);
 
     /// <summary>
     /// Gets the authenticated receiver signature from the claims.
     /// </summary>
-    public static string GetReceiverSignatureOfReceiver(this ClaimsPrincipal user) => user.GetRequiredClaimOfReceiver(ReceiverSignatureClaimTypes);
+    public static string ReceiverSignature(this ClaimsPrincipal user)
-
+        => user.GetRequiredClaimValue(EnvelopeClaimNames.ReceiverSignature);
-    /// <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);
+    public static string ReceiverMail(this ClaimsPrincipal user)
-
+        => user.GetRequiredClaimValue(JwtRegisteredClaimNames.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)
+    public static int EnvelopeId(this ClaimsPrincipal user)
     {
-        var envIdStr = user.GetRequiredClaimOfReceiver(EnvelopeIdClaimTypes);
+        var envIdStr = user.GetRequiredClaimValue(EnvelopeClaimNames.EnvelopeId);
-        if (!int.TryParse(envIdStr, out var envId))
+        if (int.TryParse(envIdStr, out var envId))
-        {
+            return envId;
-            throw new InvalidOperationException($"Claim '{"envelope_id"}' is not a valid integer.");
+        else
-        }
+            throw new InvalidOperationException($"Claim '{EnvelopeClaimNames.EnvelopeId}' is not a valid integer.");
-
-        return envId;
     }
 
     /// <summary>
-    /// 
+    /// Gets the authenticated receiver identifier from the claims.
     /// </summary>
     /// <param name="user"></param>
     /// <returns></returns>
     /// <exception cref="InvalidOperationException"></exception>
-    public static int GetReceiverIdOfReceiver(this ClaimsPrincipal user)
+    public static int ReceiverId(this ClaimsPrincipal user)
     {
-        var rcvIdStr = user.GetRequiredClaimOfReceiver(ReceiverIdClaimTypes);
+        var rcvIdStr = user.GetRequiredClaimValue(EnvelopeClaimNames.ReceiverId);
-        if (!int.TryParse(rcvIdStr, out var rcvId))
+        if (int.TryParse(rcvIdStr, out var rcvId))
-        {
+            return rcvId;
-            throw new InvalidOperationException($"Claim '{"receiver_id"}' is not a valid integer.");
+        else
-        }
+            throw new InvalidOperationException($"Claim '{EnvelopeClaimNames.ReceiverId}' is not a valid integer.");
-
-        return rcvId;
-    }
-
-    /// <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/Options/CacheOptions.cs

@@ -0,0 +1,18 @@
+namespace EnvelopeGenerator.API.Options;
+
+/// <summary>
+/// Configuration options for distributed caching.
+/// </summary>
+public sealed class CacheOptions
+{
+    /// <summary>
+    /// Configuration section name in appsettings.json.
+    /// </summary>
+    public const string SectionName = "Cache";
+
+    /// <summary>
+    /// Signature cache expiration time.
+    /// If null, signatures will not expire automatically.
+    /// </summary>
+    public TimeSpan? SignatureCacheExpiration { get; set; }
+}

EnvelopeGenerator.API/Program.cs

@@ -17,6 +17,7 @@ using Microsoft.AspNetCore.Authentication.JwtBearer;
 using Microsoft.IdentityModel.Tokens;
 using DigitalData.Core.Abstractions.Security.Extensions;
 using EnvelopeGenerator.API.Middleware;
+using EnvelopeGenerator.API.Options;
 using NLog.Web;
 using NLog;
 using DigitalData.Auth.Claims;
@@ -265,6 +266,20 @@ try
     // Localizer
     builder.Services.AddCookieBasedLocalizer();
 
+    // Cache options
+    builder.Services.Configure<CacheOptions>(config.GetSection(CacheOptions.SectionName));
+
+    // Distributed Cache - SQL Server
+    builder.Services.AddDistributedSqlServerCache(options =>
+    {
+        config.GetSection("Cache:SqlServer").Bind(options);
+        
+        if (string.IsNullOrWhiteSpace(options.ConnectionString))
+        {
+            options.ConnectionString = connStr;
+        }
+    });
+
     // Envelope generator serives
 #pragma warning disable CS0618 // Type or member is obsolete
     builder.Services

EnvelopeGenerator.API/appsettings.json

@@ -174,6 +174,14 @@
     "Receiver": [],
     "EmailTemplate": [ "TBSIG_EMAIL_TEMPLATE_AFT_UPD" ]
   },
+  "Cache": {
+    "SignatureCacheExpiration": null,
+    "SqlServer": {
+      "ConnectionString": null,
+      "SchemaName": "dbo",
+      "TableName": "TBDD_CACHE"
+    }
+  },
   "MainPageTitle": null,
   "AnnotationParams": {
     "Background": {

EnvelopeGenerator.Application/Common/Dto/DocReceiverElementDto.cs

@@ -1,6 +1,7 @@
 using EnvelopeGenerator.Domain.Constants;
 using EnvelopeGenerator.Domain.Interfaces;
 using Microsoft.AspNetCore.Mvc;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace EnvelopeGenerator.Application.Common.Dto;
 
@@ -8,7 +9,7 @@ namespace EnvelopeGenerator.Application.Common.Dto;
 /// Data Transfer Object representing a positioned element assigned to a document receiver.
 /// </summary>
 [ApiExplorerSettings(IgnoreApi = true)]
-public class SignatureDto : ISignature
+public class DocReceiverElementDto : IDocReceiverElement
 {
     /// <summary>
     /// Gets or sets the unique identifier of the element.
@@ -104,4 +105,24 @@ public class SignatureDto : ISignature
     /// 
     /// </summary>
     public SenderAppType SenderAppType { get; set; } = SenderAppType.LegacyFormApp;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? FullName { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? Position { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public string? Place { get; set; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public byte[]? Ink { get; set; }
 }

EnvelopeGenerator.Application/Common/Dto/DocumentDto.cs

@@ -31,5 +31,5 @@ public class DocumentDto
     /// <summary>
     /// Gets or sets the collection of elements associated with the document for receiver interactions, if any.
     /// </summary>
-    public IEnumerable<SignatureDto>? Elements { get; set; }
+    public IEnumerable<DocReceiverElementDto>? Elements { get; set; }
 }

EnvelopeGenerator.Application/Common/Dto/MappingProfile.cs

@@ -23,7 +23,7 @@ public class MappingProfile : Profile
     {
         // Entity to DTO mappings
         CreateMap<Config, ConfigDto>();
-        CreateMap<Signature, SignatureDto>();
+        CreateMap<DocReceiverElement, DocReceiverElementDto>();
         CreateMap<DocumentStatus, DocumentStatusDto>();
         CreateMap<EmailTemplate, EmailTemplateDto>();
         CreateMap<Envelope, EnvelopeDto>();
@@ -39,7 +39,7 @@ public class MappingProfile : Profile
 
         // DTO to Entity mappings
         CreateMap<ConfigDto, Config>();
-        CreateMap<SignatureDto, Signature>();
+        CreateMap<DocReceiverElementDto, DocReceiverElement>();
         CreateMap<DocumentStatusDto, DocumentStatus>();
         CreateMap<EmailTemplateDto, EmailTemplate>();
         CreateMap<EnvelopeDto, Envelope>();

EnvelopeGenerator.Application/Common/Dto/PsPdfKitAnnotation.cs

@@ -0,0 +1,11 @@
+using System.Dynamic;
+
+namespace EnvelopeGenerator.Application.Common.Dto;
+
+/// <summary>
+/// Represents PSPDFKit annotation data.
+/// </summary>
+/// <param name="Instant">Instant annotation data.</param>
+/// <param name="Structured">Structured annotation data.</param>
+[Obsolete("The PSPDFKit library is deprecated.")]
+public record PsPdfKitAnnotation(ExpandoObject Instant, IEnumerable<AnnotationCreateDto> Structured);

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

@@ -6,6 +6,6 @@ namespace EnvelopeGenerator.Application.Common.Interfaces.Repositories;
 /// 
 /// </summary>
 [Obsolete("Use IRepository")]
-public interface IDocumentReceiverElementRepository : ICRUDRepository<Signature, int>
+public interface IDocumentReceiverElementRepository : ICRUDRepository<DocReceiverElement, int>
 {
 }

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

@@ -8,6 +8,6 @@ namespace EnvelopeGenerator.Application.Common.Interfaces.Services;
 /// 
 /// </summary>
 [Obsolete("Use MediatR")]
-public interface IDocumentReceiverElementService : IBasicCRUDService<SignatureDto, Signature, int>
+public interface IDocumentReceiverElementService : IBasicCRUDService<DocReceiverElementDto, DocReceiverElement, int>
 {
 }

EnvelopeGenerator.Application/Common/Notifications/DocSigned/DocSignedNotification.cs

@@ -1,88 +1,37 @@
 using EnvelopeGenerator.Application.Common.Dto;
 using EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiver;
 using EnvelopeGenerator.Application.Common.Extensions;
-using EnvelopeGenerator.Application.Common.Notifications.RemoveSignature;
 using EnvelopeGenerator.Domain.Constants;
 using MediatR;
-using System.Dynamic;
 
 namespace EnvelopeGenerator.Application.Common.Notifications.DocSigned;
 
 /// <summary>
-/// 
+/// Notification raised when a document is signed by a receiver.
 /// </summary>
-/// <param name="Instant"></param>
+[Obsolete("This notification is deprecated. Use Signature.Commands.SignCommand instead.")]
-/// <param name="Structured"></param>
+public record DocSignedNotification : INotification, ISendMailNotification
-public record PsPdfKitAnnotation(ExpandoObject Instant, IEnumerable<AnnotationCreateDto> Structured);
-
-/// <summary>
-/// 
-/// </summary>
-/// <param name="Original"></param>
-public record DocSignedNotification(EnvelopeReceiverDto Original) : EnvelopeReceiverDto(Original), INotification, ISendMailNotification
 {
     /// <summary>
-    /// 
+    /// The envelope receiver information.
     /// </summary>
+    public required EnvelopeReceiverDto EnvelopeReceiver { get; init; }
+
+    /// <summary>
+    /// The PSPDFKit annotation data.
+    /// </summary>
+    [Obsolete("The PSPDFKit library is deprecated.")]
     public PsPdfKitAnnotation? PsPdfKitAnnotation { get; init; }
 
     /// <summary>
-    /// 
+    /// Gets the email template type.
     /// </summary>
     public EmailTemplateType TemplateType => EmailTemplateType.DocumentSigned;
 
     /// <summary>
-    /// 
+    /// Gets the email address of the receiver.
     /// </summary>
-    public string EmailAddress => Receiver?.EmailAddress
+    public string EmailAddress => EnvelopeReceiver.Receiver?.EmailAddress
         ?? throw new InvalidOperationException($"Receiver is null." +
             $"DocSignedNotification:\n{this.ToJson(Format.Json.ForDiagnostics)}");
-}
-
-/// <summary>
-/// 
-/// </summary>
-public static class DocSignedNotificationExtensions
-{
-    /// <summary>
-    /// Converts an <see cref="EnvelopeReceiverDto"/> to a <see cref="DocSignedNotification"/>.
-    /// </summary>
-    /// <param name="dto">The DTO to convert.</param>
-    /// <param name="psPdfKitAnnotation"></param>
-    /// <returns>A new <see cref="DocSignedNotification"/> instance.</returns>
-    public static DocSignedNotification ToDocSignedNotification(this EnvelopeReceiverDto dto, PsPdfKitAnnotation psPdfKitAnnotation)
-        => new(dto) { PsPdfKitAnnotation = psPdfKitAnnotation };
-
-    /// <summary>
-    /// 
-    /// </summary>
-    /// <param name="dtoTask"></param>
-    /// <param name="psPdfKitAnnotation"></param>
-    /// <returns></returns>
-    public static async Task<DocSignedNotification?> ToDocSignedNotification(this Task<EnvelopeReceiverDto?> dtoTask, PsPdfKitAnnotation? psPdfKitAnnotation)
-        => await dtoTask is EnvelopeReceiverDto dto ? new(dto) { PsPdfKitAnnotation = psPdfKitAnnotation } : null;
-
-    /// <summary>
-    /// 
-    /// </summary>
-    /// <param name="publisher"></param>
-    /// <param name="notification"></param>
-    /// <param name="cancel"></param>
-    /// <returns></returns>
-    public static async Task PublishSafely(this IPublisher publisher, DocSignedNotification notification, CancellationToken cancel = default)
-    {
-        try
-        {
-            await publisher.Publish(notification, cancel);
-        }
-        catch (Exception)
-        {
-            await publisher.Publish(new RemoveSignatureNotification()
-            {
-                EnvelopeId = notification.EnvelopeId,
-                ReceiverId = notification.ReceiverId
-            }, cancel);
-            throw;
-        }
-    }
 }

EnvelopeGenerator.Application/Common/Notifications/DocSigned/Handlers/AnnotationHandler.cs

@@ -1,5 +1,6 @@
 using DigitalData.Core.Abstraction.Application.Repository;
 using EnvelopeGenerator.Domain.Entities;
+using EnvelopeGenerator.Application.Common.Dto;
 using MediatR;
 
 namespace EnvelopeGenerator.Application.Common.Notifications.DocSigned.Handlers;
@@ -7,6 +8,7 @@ namespace EnvelopeGenerator.Application.Common.Notifications.DocSigned.Handlers;
 /// <summary>
 /// 
 /// </summary>
+[Obsolete("The PSPDFKit library is deprecated.")]
 public class AnnotationHandler : INotificationHandler<DocSignedNotification>
 {
     /// <summary>

EnvelopeGenerator.Application/Common/Notifications/DocSigned/Handlers/DocStatusHandler.cs

@@ -1,4 +1,5 @@
 using EnvelopeGenerator.Application.DocStatus.Commands;
+using EnvelopeGenerator.Application.Common.Dto;
 using EnvelopeGenerator.Domain.Constants;
 using MediatR;
 using System.Text.Json;
@@ -8,6 +9,7 @@ namespace EnvelopeGenerator.Application.Common.Notifications.DocSigned.Handlers;
 /// <summary>
 /// 
 /// </summary>
+[Obsolete("This notification is deprecated. Use Signature.Commands.SignCommand instead.")]
 public class DocStatusHandler : INotificationHandler<DocSignedNotification>
 {
     private const string BlankAnnotationJson = "{}";
@@ -29,10 +31,11 @@ public class DocStatusHandler : INotificationHandler<DocSignedNotification>
     /// <param name="notification"></param>
     /// <param name="cancel"></param>
     /// <returns></returns>
+    [Obsolete("This notification is deprecated. Use Signature.Commands.SignCommand instead.")]
     public Task Handle(DocSignedNotification notification, CancellationToken cancel) => _sender.Send(new CreateDocStatusCommand()
     {
-        EnvelopeId = notification.EnvelopeId,
+        EnvelopeId = notification.EnvelopeReceiver.EnvelopeId,
-        ReceiverId = notification.ReceiverId,
+        ReceiverId = notification.EnvelopeReceiver.ReceiverId,
         Value = notification.PsPdfKitAnnotation is PsPdfKitAnnotation annot
                     ? JsonSerializer.Serialize(annot.Instant, Format.Json.ForAnnotations)
                     : BlankAnnotationJson

EnvelopeGenerator.Application/Common/Notifications/DocSigned/Handlers/HistoryHandler.cs

@@ -29,13 +29,13 @@ public class HistoryHandler : INotificationHandler<DocSignedNotification>
     /// <returns></returns>
     public async Task Handle(DocSignedNotification notification, CancellationToken cancel)
     {
-        if (notification.Receiver is null)
+        if (notification.EnvelopeReceiver.Receiver is null)
             throw new InvalidOperationException($"Receiver information is missing in the notification. DocSignedNotification:\n {notification.ToJson(Format.Json.ForDiagnostics)}");
 
         await _sender.Send(new CreateHistoryCommand()
         {
-            EnvelopeId = notification.EnvelopeId,
+            EnvelopeId = notification.EnvelopeReceiver.EnvelopeId,
-            UserReference = notification.Receiver.EmailAddress,
+            UserReference = notification.EnvelopeReceiver.Receiver.EmailAddress,
             Status = EnvelopeStatus.DocumentSigned,
         }, cancel);
     }

EnvelopeGenerator.Application/Common/Notifications/DocSigned/Handlers/SendSignedMailHandler.cs

@@ -31,7 +31,7 @@ public class SendSignedMailHandler : SendMailHandler<DocSignedNotification>
     protected override void ConfigureEmailOut(DocSignedNotification notification, EmailOut emailOut)
     {
         emailOut.ReferenceString = notification.EmailAddress;
-        emailOut.ReferenceId = notification.ReceiverId;
+        emailOut.ReferenceId = notification.EnvelopeReceiver.ReceiverId;
     }
 
     /// <summary>
@@ -42,11 +42,11 @@ public class SendSignedMailHandler : SendMailHandler<DocSignedNotification>
     {
         var placeHolders = new Dictionary<string, string>()
         {
-            { "[NAME_RECEIVER]", notification.Name ?? string.Empty },
+            { "[NAME_RECEIVER]", notification.EnvelopeReceiver.Name ?? string.Empty },
-            { "[DOCUMENT_TITLE]", notification.Envelope?.Title ?? string.Empty },
+            { "[DOCUMENT_TITLE]", notification.EnvelopeReceiver.Envelope?.Title ?? string.Empty },
         };
 
-        if (notification.Envelope.IsReadAndConfirm())
+        if (notification.EnvelopeReceiver.Envelope.IsReadAndConfirm())
         {
             placeHolders["[SIGNATURE_TYPE]"] = "Lesen und bestätigen";
             placeHolders["[DOCUMENT_PROCESS]"] = string.Empty;

EnvelopeGenerator.Application/DependencyInjection.cs

@@ -7,6 +7,9 @@ using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using QRCoder;
 using System.Reflection;
+using MediatR;
+using EnvelopeGenerator.Application.DocReceiverElements.Commands;
+using EnvelopeGenerator.Application.DocReceiverElements.Behaviors;
 
 namespace EnvelopeGenerator.Application;
 
@@ -56,6 +59,22 @@ public static class DependencyInjection
         services.AddMediatR(cfg =>
         {
             cfg.RegisterServicesFromAssembly(Assembly.GetExecutingAssembly());
+            
+            // Register SignCommand pipeline behaviors in execution order
+            // 0. EnvelopeReceiverResolutionBehavior - Resolves EnvelopeReceiver from query parameters (executes FIRST)
+            cfg.AddBehavior<IPipelineBehavior<SigningCommand, Unit>, EnvelopeReceiverResolutionBehavior>();
+            
+            // 1. AnnotationBehavior - Saves annotations (executes second)
+            cfg.AddBehavior<IPipelineBehavior<SigningCommand, Unit>, AnnotationBehavior>();
+            
+            // 2. DocStatusBehavior - Creates document status (executes third)
+            cfg.AddBehavior<IPipelineBehavior<SigningCommand, Unit>, DocStatusBehavior>();
+
+            // 3. HistoryBehavior - Records history (executes fourth)
+            cfg.AddBehavior<IPipelineBehavior<SigningCommand, Unit>, HistoryBehavior>();
+            
+            // 4. SendSignedMailBehavior - Sends notification email (executes LAST, only if all previous succeed)
+            cfg.AddBehavior<IPipelineBehavior<SigningCommand, Unit>, SendSignedMailBehavior>();
         });
 
         return services;

EnvelopeGenerator.Application/DocReceiverElements/Behaviors/AnnotationBehavior.cs

@@ -0,0 +1,41 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using EnvelopeGenerator.Application.Common.Dto;
+using EnvelopeGenerator.Application.DocReceiverElements.Commands;
+using EnvelopeGenerator.Domain.Entities;
+using MediatR;
+
+namespace EnvelopeGenerator.Application.DocReceiverElements.Behaviors;
+
+/// <summary>
+/// Pipeline behavior that saves annotations.
+/// Executes first in the signing process.
+/// </summary>
+[Obsolete("This notification is deprecated. Use Signature.Commands.SignCommand instead.")]
+public class AnnotationBehavior : IPipelineBehavior<SigningCommand, Unit>
+{
+    private readonly IRepository<ElementAnnotation> _repo;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="repository"></param>
+    public AnnotationBehavior(IRepository<ElementAnnotation> repository)
+    {
+        _repo = repository;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="request"></param>
+    /// <param name="next"></param>
+    /// <param name="cancellationToken"></param>
+    /// <returns></returns>
+    public async Task<Unit> Handle(SigningCommand request, RequestHandlerDelegate<Unit> next, CancellationToken cancellationToken)
+    {
+        if (request.PsPdfKitAnnotation is PsPdfKitAnnotation annot)
+            await _repo.CreateAsync(annot.Structured, cancellationToken);
+
+        return await next(cancellationToken);
+    }
+}

EnvelopeGenerator.Application/DocReceiverElements/Behaviors/DocStatusBehavior.cs

@@ -0,0 +1,50 @@
+using EnvelopeGenerator.Application.Common.Dto;
+using EnvelopeGenerator.Application.DocStatus.Commands;
+using EnvelopeGenerator.Application.DocReceiverElements.Commands;
+using EnvelopeGenerator.Domain.Constants;
+using MediatR;
+using System.Text.Json;
+
+namespace EnvelopeGenerator.Application.DocReceiverElements.Behaviors;
+
+/// <summary>
+/// Pipeline behavior that creates document status.
+/// Executes second in the signing process.
+/// </summary>
+public class DocStatusBehavior : IPipelineBehavior<SigningCommand, Unit>
+{
+    private const string BlankAnnotationJson = "{}";
+
+    private readonly ISender _sender;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="sender"></param>
+    public DocStatusBehavior(ISender sender)
+    {
+        _sender = sender;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="request"></param>
+    /// <param name="next"></param>
+    /// <param name="cancellationToken"></param>
+    /// <returns></returns>
+    [Obsolete("This notification is deprecated. Use Signature.Commands.SignCommand instead.")]
+    public async Task<Unit> Handle(SigningCommand request, RequestHandlerDelegate<Unit> next, CancellationToken cancellationToken)
+    {
+        await _sender.Send(new CreateDocStatusCommand()
+        {
+            EnvelopeId = request.EnvelopeReceiver.EnvelopeId,
+            ReceiverId = request.EnvelopeReceiver.ReceiverId,
+            Value = request.PsPdfKitAnnotation is PsPdfKitAnnotation annot
+                        ? JsonSerializer.Serialize(annot.Instant, Format.Json.ForAnnotations)
+                        : BlankAnnotationJson
+        }, cancellationToken);
+
+        return await next(cancellationToken);
+    }
+}

EnvelopeGenerator.Application/DocReceiverElements/Behaviors/EnvelopeReceiverResolutionBehavior.cs

@@ -0,0 +1,54 @@
+using AutoMapper;
+using DigitalData.Core.Abstraction.Application.Repository;
+using DigitalData.Core.Exceptions;
+using EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiver;
+using EnvelopeGenerator.Application.Common.Extensions;
+using EnvelopeGenerator.Application.DocReceiverElements.Commands;
+using EnvelopeGenerator.Domain.Entities;
+using MediatR;
+using Microsoft.EntityFrameworkCore;
+
+namespace EnvelopeGenerator.Application.DocReceiverElements.Behaviors;
+
+/// <summary>
+/// Pipeline behavior that resolves and validates EnvelopeReceiver.
+/// Executes FIRST in the signing process - before all other behaviors.
+/// If EnvelopeReceiver is not provided, it queries the database using EnvelopeReceiverQueryBase parameters.
+/// </summary>
+public class EnvelopeReceiverResolutionBehavior : IPipelineBehavior<SigningCommand, Unit>
+{
+    private readonly IRepository<EnvelopeReceiver> _erRepo;
+    private readonly IMapper _mapper;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="erRepo"></param>
+    /// <param name="mapper"></param>
+    public EnvelopeReceiverResolutionBehavior(IRepository<EnvelopeReceiver> erRepo, IMapper mapper)
+    {
+        _erRepo = erRepo;
+        _mapper = mapper;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="request"></param>
+    /// <param name="next"></param>
+    /// <param name="cancellationToken"></param>
+    /// <returns></returns>
+    public async Task<Unit> Handle(SigningCommand request, RequestHandlerDelegate<Unit> next, CancellationToken cancellationToken)
+    {
+        // If EnvelopeReceiver is not provided, query it from database
+        if (request.EnvelopeReceiver is null)
+        {
+            var er = await _erRepo.Query.Where(request, notnull: true).SingleOrDefaultAsync(cancellationToken)
+                ?? throw new NotFoundException("EnvelopeReceiver not found");
+
+            request.SetEnvelopeReceiver(_mapper.Map<EnvelopeReceiverDto>(er));
+        }
+
+        return await next(cancellationToken);
+    }
+}

EnvelopeGenerator.Application/DocReceiverElements/Behaviors/HistoryBehavior.cs

@@ -0,0 +1,47 @@
+using EnvelopeGenerator.Application.Common.Extensions;
+using EnvelopeGenerator.Application.Histories.Commands;
+using EnvelopeGenerator.Application.DocReceiverElements.Commands;
+using EnvelopeGenerator.Domain.Constants;
+using MediatR;
+
+namespace EnvelopeGenerator.Application.DocReceiverElements.Behaviors;
+
+/// <summary>
+/// Pipeline behavior that records history.
+/// Executes third in the signing process.
+/// </summary>
+public class HistoryBehavior : IPipelineBehavior<SigningCommand, Unit>
+{
+    private readonly ISender _sender;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="sender"></param>
+    public HistoryBehavior(ISender sender)
+    {
+        _sender = sender;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="request"></param>
+    /// <param name="next"></param>
+    /// <param name="cancellationToken"></param>
+    /// <returns></returns>
+    public async Task<Unit> Handle(SigningCommand request, RequestHandlerDelegate<Unit> next, CancellationToken cancellationToken)
+    {
+        if (request.EnvelopeReceiver.Receiver is null)
+            throw new InvalidOperationException($"Receiver information is missing in the notification. SignCommand:\n {request.ToJson(Format.Json.ForDiagnostics)}");
+
+        await _sender.Send(new CreateHistoryCommand()
+        {
+            EnvelopeId = request.EnvelopeReceiver.EnvelopeId,
+            UserReference = request.EnvelopeReceiver.Receiver.EmailAddress,
+            Status = EnvelopeStatus.DocumentSigned,
+        }, cancellationToken);
+
+        return await next(cancellationToken);
+    }
+}

EnvelopeGenerator.Application/DocReceiverElements/Behaviors/SaveSignatureBehavior.cs

@@ -0,0 +1,51 @@
+using EnvelopeGenerator.Application.Common.Dto;
+using EnvelopeGenerator.Application.DocStatus.Commands;
+using EnvelopeGenerator.Domain.Constants;
+using MediatR;
+using System.Text.Json;
+
+<<<<<<< TODO: Unmerged change from project 'EnvelopeGenerator.Application (net8.0)', Before:
+=======
+using EnvelopeGenerator.Application.DocReceiverElements.Commands.SigningCommand.SigningCommand;
+using EnvelopeGenerator.Application.DocReceiverElements.Commands.SigningCommand;
+>>>>>>> After
+
+<<<<<<< TODO: Unmerged change from project 'EnvelopeGenerator.Application (net9.0)', Before:
+=======
+using EnvelopeGenerator.Application.DocReceiverElements.Commands.SigningCommand;
+>>>>>>> After
+using EnvelopeGenerator.Application.DocReceiverElements.Commands.SigningCommand.SigningCommand.SigningCommand;
+using EnvelopeGenerator.Application.DocReceiverElements.Commands.SigningCommand.SigningCommand;
+using EnvelopeGenerator.Application.DocReceiverElements.Commands.SigningCommand;
+
+namespace EnvelopeGenerator.Application.DocReceiverElements.Behaviors;
+
+/// <summary>
+/// Pipeline behavior that creates document status.
+/// Executes second in the signing process.
+/// </summary>
+public class SaveSignatureBehavior : IPipelineBehavior<SigningCommand, Unit>
+{
+    private readonly ISender _sender;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="sender"></param>
+    public SaveSignatureBehavior(ISender sender)
+    {
+        _sender = sender;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="request"></param>
+    /// <param name="next"></param>
+    /// <param name="cancellationToken"></param>
+    /// <returns></returns>
+    public async Task<Unit> Handle(SigningCommand request, RequestHandlerDelegate<Unit> next, CancellationToken cancellationToken)
+    {
+        return await next(cancellationToken);
+    }
+}

EnvelopeGenerator.Application/DocReceiverElements/Behaviors/SendSignedMailBehavior.cs

@@ -0,0 +1,122 @@
+using DigitalData.Core.Abstraction.Application.Repository;
+using DigitalData.EmailProfilerDispatcher.Abstraction.Entities;
+using EnvelopeGenerator.Application.Common.Configurations;
+using EnvelopeGenerator.Application.Common.Extensions;
+using EnvelopeGenerator.Application.DocReceiverElements.Commands;
+using EnvelopeGenerator.Domain.Constants;
+using EnvelopeGenerator.Domain.Entities;
+using EnvelopeGenerator.Domain.Interfaces;
+using MediatR;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Options;
+using Newtonsoft.Json;
+
+namespace EnvelopeGenerator.Application.DocReceiverElements.Behaviors;
+
+/// <summary>
+/// Pipeline behavior that sends signed mail notification.
+/// Executes LAST in the signing process - only if all previous behaviors succeed.
+/// </summary>
+public class SendSignedMailBehavior : IPipelineBehavior<SigningCommand, Unit>
+{
+    private readonly IRepository<EmailTemplate> _tempRepo;
+    private readonly IRepository<EmailOut> _emailOutRepo;
+    private readonly MailParams _mailParams;
+    private readonly DispatcherParams _dispatcherParams;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="tempRepo"></param>
+    /// <param name="emailOutRepo"></param>
+    /// <param name="mailParamsOptions"></param>
+    /// <param name="dispatcherParamsOptions"></param>
+    public SendSignedMailBehavior(
+        IRepository<EmailTemplate> tempRepo,
+        IRepository<EmailOut> emailOutRepo,
+        IOptions<MailParams> mailParamsOptions,
+        IOptions<DispatcherParams> dispatcherParamsOptions)
+    {
+        _tempRepo = tempRepo;
+        _emailOutRepo = emailOutRepo;
+        _mailParams = mailParamsOptions.Value;
+        _dispatcherParams = dispatcherParamsOptions.Value;
+    }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="request"></param>
+    /// <param name="next"></param>
+    /// <param name="cancellationToken"></param>
+    /// <returns></returns>
+    public async Task<Unit> Handle(SigningCommand request, RequestHandlerDelegate<Unit> next, CancellationToken cancellationToken)
+    {
+        var placeHolders = CreatePlaceHolders(request);
+
+        var temp = await _tempRepo
+            .Where(x => x.Name == EmailTemplateType.DocumentSigned.ToString())
+            .SingleOrDefaultAsync(cancellationToken)
+                ?? throw new InvalidOperationException($"Email template not found. SignCommand:\n {request.ToJson(Format.Json.ForDiagnostics)}");
+
+        temp.Subject = ReplacePlaceHolders(temp.Subject, placeHolders, _mailParams.Placeholders);
+        temp.Body = ReplacePlaceHolders(temp.Body, placeHolders, _mailParams.Placeholders);
+
+        var emailOut = new EmailOut
+        {
+            EmailAddress = request.EnvelopeReceiver.Receiver!.EmailAddress,
+            EmailBody = temp.Body,
+            EmailSubj = temp.Subject,
+            AddedWhen = DateTime.Now,
+            AddedWho = _dispatcherParams.AddedWho,
+            SendingProfile = _dispatcherParams.SendingProfile,
+            ReminderTypeId = _dispatcherParams.ReminderTypeId,
+            EmailAttmt1 = _dispatcherParams.EmailAttmt1,
+            WfId = (int)EnvelopeStatus.MessageConfirmationSent,
+            ReferenceString = request.EnvelopeReceiver.Receiver!.EmailAddress,
+            ReferenceId = request.EnvelopeReceiver.ReceiverId
+        };
+
+        await _emailOutRepo.CreateAsync(emailOut, cancellationToken);
+
+        return await next(cancellationToken);
+    }
+
+    private Dictionary<string, string> CreatePlaceHolders(SigningCommand request)
+    {
+        var placeHolders = new Dictionary<string, string>()
+        {
+            { "[NAME_RECEIVER]", request.EnvelopeReceiver.Name ?? string.Empty },
+            { "[DOCUMENT_TITLE]", request.EnvelopeReceiver.Envelope?.Title ?? string.Empty },
+        };
+
+        if (request.EnvelopeReceiver.Envelope.IsReadAndConfirm())
+        {
+            placeHolders["[SIGNATURE_TYPE]"] = "Lesen und bestätigen";
+            placeHolders["[DOCUMENT_PROCESS]"] = string.Empty;
+            placeHolders["[FINAL_STATUS]"] = "Lesebestätigung";
+            placeHolders["[FINAL_ACTION]"] = "Empfänger bestätigt";
+            placeHolders["[REJECTED_BY_OTHERS]"] = "anderen Empfänger abgelehnt!";
+            placeHolders["[RECEIVER_ACTION]"] = "bestätigt";
+        }
+        else
+        {
+            placeHolders["[SIGNATURE_TYPE]"] = "Signieren";
+            placeHolders["[DOCUMENT_PROCESS]"] = " und elektronisch unterschreiben";
+            placeHolders["[FINAL_STATUS]"] = "Signatur";
+            placeHolders["[FINAL_ACTION]"] = "Vertragspartner unterzeichnet";
+            placeHolders["[REJECTED_BY_OTHERS]"] = "anderen Vertragspartner abgelehnt! Ihre notwendige Unterzeichnung wurde verworfen.";
+            placeHolders["[RECEIVER_ACTION]"] = "unterschrieben";
+        }
+
+        return placeHolders;
+    }
+
+    private static string ReplacePlaceHolders(string text, params Dictionary<string, string>[] placeHoldersList)
+    {
+        foreach (var placeHolders in placeHoldersList)
+            foreach (var ph in placeHolders)
+                text = text.Replace(ph.Key, ph.Value);
+        return text;
+    }
+}

EnvelopeGenerator.Application/DocReceiverElements/Commands/SigningCommand.cs

@@ -0,0 +1,121 @@
+using MediatR;
+using EnvelopeGenerator.Application.Common.Dto;
+using EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiver;
+using EnvelopeGenerator.Application.Common.Query;
+
+namespace EnvelopeGenerator.Application.DocReceiverElements.Commands;
+
+/// <summary>
+/// Represents a captured signature with metadata created by the receiver in the signature popup.
+/// This model holds the signature image (as base64 data URL) along with signer information
+/// used for rendering applied signatures on the PDF canvas.
+/// </summary>
+/// <remarks>
+/// <b>Used in:</b> EnvelopeViewer.razor signature popup workflow
+/// <br/>
+/// <b>Creation:</b> User draws/types/uploads signature and fills required fields
+/// </remarks>
+public sealed record SignatureDto
+{
+    /// <summary>
+    /// TBDD_DOCUMENT_RECEIVER_ELEMENT.ID - identifies the specific signature field on the PDF page.
+    /// </summary>
+    public required int ElementId { get; init; }
+
+    /// <summary>
+    /// Base64-encoded data URL of the signature image.
+    /// <br/>
+    /// <b>Format:</b> <c>data:image/png;base64,iVBORw0KG...</c>
+    /// <br/>
+    /// <b>Source:</b> Canvas.toDataURL() from signature pad (draw/text/image tabs)
+    /// <br/>
+    /// <b>Usage:</b> Set as <c>img.src</c> in applied signature overlay
+    /// </summary>
+    public required string DataUrl { get; init; }
+
+    /// <summary>
+    /// Full name of the signer (first and last name).
+    /// <br/>
+    /// <b>Required:</b> Yes (validated in popup)
+    /// <br/>
+    /// <b>Example:</b> "Max Mustermann"
+    /// </summary>
+    public required string FullName { get; init; }
+
+    private readonly string? _position = null;
+
+    /// <summary>
+    /// Job title or position of the signer.
+    /// <br/>
+    /// <b>Required:</b> No (optional field)
+    /// <br/>
+    /// <b>Example:</b> "Geschäftsführer" or empty string
+    /// </summary>
+    public string? Position
+    {
+        get => _position;
+        init => _position = string.IsNullOrWhiteSpace(value) ? value : null;
+    }
+
+    /// <summary>
+    /// Location/place where the signature was created.
+    /// <br/>
+    /// <b>Required:</b> Yes (validated in popup)
+    /// <br/>
+    /// <b>Display:</b> Shown with current date in German format (dd.MM.yyyy)
+    /// <br/>
+    /// <b>Example:</b> "Berlin" ? rendered as "Berlin, 26.01.2025"
+    /// </summary>
+    public required string Place { get; init; }
+}
+
+/// <summary>
+/// Command to sign a document by a receiver.
+/// </summary>
+public record SigningCommand : EnvelopeReceiverQueryBase, IRequest
+{
+    private EnvelopeReceiverDto? _envelopeReceiver;
+
+    internal void SetEnvelopeReceiver(EnvelopeReceiverDto envelopeReceiver)
+    {
+        _envelopeReceiver = envelopeReceiver;
+    }
+
+    /// <summary>
+    /// The envelope receiver information.
+    /// </summary>
+    public EnvelopeReceiverDto EnvelopeReceiver
+    { 
+        get => _envelopeReceiver!;
+        init => _envelopeReceiver = value;
+    }
+
+    /// <summary>
+    /// The PSPDFKit annotation data.
+    /// </summary>
+    [Obsolete("This notification is deprecated. Use Signature.Commands.SignCommand instead.")]
+    public PsPdfKitAnnotation? PsPdfKitAnnotation { get; init; }
+
+    /// <summary>
+    /// 
+    /// </summary>
+    public IEnumerable<SignatureDto>? Signatures { get; init; }
+}
+
+/// <summary>
+/// Handles the sign command. All work is done by pipeline behaviors.
+/// This handler is intentionally empty - behaviors handle all the processing.
+/// </summary>
+public class SignCommandHandler : IRequestHandler<SigningCommand>
+{
+    /// <summary>
+    /// Executes the signing command. Pipeline behaviors handle all processing.
+    /// </summary>
+    /// <param name="request"></param>
+    /// <param name="cancellationToken"></param>
+    /// <returns></returns>
+    public Task Handle(SigningCommand request, CancellationToken cancellationToken = default)
+    {
+        return Task.CompletedTask;
+    }
+}

EnvelopeGenerator.Application/DocReceiverElements/MappingProfile.cs

@@ -0,0 +1,19 @@
+using AutoMapper;
+using EnvelopeGenerator.Application.DocReceiverElements.Commands;
+using EnvelopeGenerator.Domain.Entities;
+
+namespace EnvelopeGenerator.Application.DocReceiverElements;
+
+/// <summary>
+///
+/// </summary>
+public class MappingProfile : Profile
+{
+    /// <summary>
+    ///
+    /// </summary>
+    public MappingProfile()
+    {
+        CreateMap<SignatureDto, DocReceiverElement>();
+    }
+}

EnvelopeGenerator.Application/EnvelopeReceivers/Commands/CreateEnvelopeReceiverCommand.cs

@@ -29,7 +29,7 @@ public record CreateEnvelopeReceiverCommand : CreateEnvelopeCommand, IRequest<Cr
 /// <param name="X">X-Position</param>
 /// <param name="Y">Y-Position</param>
 /// <param name="Page">Seite, auf der sie sich befindet</param>
-public record Signature([Required] double X, [Required] double Y, [Required] int Page);
+public record DocReceiverElementCreateDto([Required] double X, [Required] double Y, [Required] int Page);
 
 /// <summary>
 /// DTO für Empfänger, die erstellt oder abgerufen werden sollen.
@@ -41,7 +41,7 @@ public class ReceiverGetOrCreateCommand
     /// Unterschriften auf Dokumenten.
     /// </summary>
     [Required]
-    public List<Signature> Signatures { get; init; } = new();
+    public List<DocReceiverElementCreateDto> DocReceiverElements { get; init; } = new();
 
     /// <summary>
     /// Der Name, mit dem der Empfänger angesprochen werden soll.

EnvelopeGenerator.Application/Services/DocumentReceiverElementService.cs

@@ -1,9 +1,9 @@
 using AutoMapper;
 using DigitalData.Core.Application;
-using EnvelopeGenerator.Domain.Entities;
 using EnvelopeGenerator.Application.Common.Dto;
 using EnvelopeGenerator.Application.Common.Interfaces.Repositories;
 using EnvelopeGenerator.Application.Common.Interfaces.Services;
+using EnvelopeGenerator.Domain.Entities;
 
 namespace EnvelopeGenerator.Application.Services;
 
@@ -11,7 +11,7 @@ namespace EnvelopeGenerator.Application.Services;
 /// 
 /// </summary>
 [Obsolete("Use MediatR")]
-public class DocumentReceiverElementService : BasicCRUDService<IDocumentReceiverElementRepository, SignatureDto, Signature, int>, IDocumentReceiverElementService
+public class DocumentReceiverElementService : BasicCRUDService<IDocumentReceiverElementRepository, DocReceiverElementDto, DocReceiverElement, int>, IDocumentReceiverElementService
 {
     /// <summary>
     /// 

EnvelopeGenerator.BBTests/frmFinalizePDF.vb

@@ -164,7 +164,7 @@ Public Class frmFinalizePDF
                     Return
                 End If
 
-                Dim sigRepo = scope.ServiceProvider.Repository(Of Signature)()
+                Dim sigRepo = scope.ServiceProvider.Repository(Of DocReceiverElement)()
                 Dim elements = sigRepo _
                     .Where(Function(sig) sig.Document.EnvelopeId = envelopeId) _
                     .Include(Function(sig) sig.Annotations) _

EnvelopeGenerator.CommonServices/Jobs/FinalizeDocument/PDFBurner.vb

@@ -46,7 +46,7 @@ Namespace Jobs.FinalizeDocument
                     Return pSourceBuffer
                 End If
 
-                Dim sigRepo = scope.ServiceProvider.Repository(Of Signature)()
+                Dim sigRepo = scope.ServiceProvider.Repository(Of DocReceiverElement)()
                 Dim elements = sigRepo _
                     .Where(Function(sig) sig.Document.EnvelopeId = envelopeId) _
                     .Include(Function(sig) sig.Annotations) _
@@ -58,7 +58,7 @@ Namespace Jobs.FinalizeDocument
             End Using
         End Function
 
-        Public Function BurnElementAnnotsToPDF(pSourceBuffer As Byte(), elements As List(Of Signature)) As Byte()
+        Public Function BurnElementAnnotsToPDF(pSourceBuffer As Byte(), elements As List(Of DocReceiverElement)) As Byte()
             ' Add background
             Using doc As Pdf(Of MemoryStream, MemoryStream) = Pdf.FromMemory(pSourceBuffer)
                 'TODO: take the length from the largest y

EnvelopeGenerator.CommonServices/Models/ElementModel.vb

@@ -10,8 +10,8 @@ Public Class ElementModel
         MyBase.New(pState)
     End Sub
 
-    Private Function ToElement(pRow As DataRow) As Signature
+    Private Function ToElement(pRow As DataRow) As DocReceiverElement
-        Return New Signature() With {
+        Return New DocReceiverElement() With {
             .Id = pRow.ItemEx("GUID", 0),
             .DocumentId = pRow.ItemEx("DOCUMENT_ID", 0),
             .ReceiverId = pRow.ItemEx("RECEIVER_ID", 0),
@@ -24,7 +24,7 @@ Public Class ElementModel
         }
     End Function
 
-    Private Function ToElements(pTable As DataTable) As List(Of Signature)
+    Private Function ToElements(pTable As DataTable) As List(Of DocReceiverElement)
         Return pTable?.Rows.Cast(Of DataRow).
                 Select(AddressOf ToElement).
                 ToList()
@@ -80,7 +80,7 @@ Public Class ElementModel
         End Try
     End Function
 
-    Public Function List(pDocumentId As Integer) As List(Of Signature)
+    Public Function List(pDocumentId As Integer) As List(Of DocReceiverElement)
         Try
             Dim oSql = $"SELECT * FROM [dbo].[TBSIG_DOCUMENT_RECEIVER_ELEMENT] WHERE DOCUMENT_ID = {pDocumentId} ORDER BY PAGE ASC"
             Dim oTable = Database.GetDatatable(oSql)
@@ -93,7 +93,7 @@ Public Class ElementModel
         End Try
     End Function
 
-    Public Function List(pDocumentId As Integer, pReceiverId As Integer) As List(Of Signature)
+    Public Function List(pDocumentId As Integer, pReceiverId As Integer) As List(Of DocReceiverElement)
         Try
             Dim oReceiverConstraint = ""
             If pReceiverId > 0 Then
@@ -111,7 +111,7 @@ Public Class ElementModel
         End Try
     End Function
 
-    Public Function Insert(pElement As Signature) As Boolean
+    Public Function Insert(pElement As DocReceiverElement) As Boolean
         Try
             Dim oSql = "INSERT INTO [dbo].[TBSIG_DOCUMENT_RECEIVER_ELEMENT]
                    ([DOCUMENT_ID]
@@ -161,7 +161,7 @@ Public Class ElementModel
         End Try
     End Function
 
-    Public Function Update(pElement As Signature) As Boolean
+    Public Function Update(pElement As DocReceiverElement) As Boolean
         Try
             Dim oSql = "UPDATE [dbo].[TBSIG_DOCUMENT_RECEIVER_ELEMENT]
                    SET [POSITION_X] = @POSITION_X
@@ -185,7 +185,7 @@ Public Class ElementModel
         End Try
     End Function
 
-    Private Function GetElementId(pElement As Signature) As Integer
+    Private Function GetElementId(pElement As DocReceiverElement) As Integer
         Try
             Return Database.GetScalarValue($"SELECT MAX(GUID) FROM TBSIG_DOCUMENT_RECEIVER_ELEMENT 
                 WHERE DOCUMENT_ID = {pElement.DocumentId} AND RECEIVER_ID = {pElement.ReceiverId}")
@@ -196,7 +196,7 @@ Public Class ElementModel
         End Try
     End Function
 
-    Public Function DeleteElement(pElement As Signature) As Boolean
+    Public Function DeleteElement(pElement As DocReceiverElement) As Boolean
         Try
             Dim oSql = $"DELETE FROM TBSIG_DOCUMENT_RECEIVER_ELEMENT WHERE GUID = {pElement.Id}"
             Return Database.ExecuteNonQuery(oSql)

EnvelopeGenerator.Domain/Entities/DocReceiverElement.cs

@@ -11,9 +11,9 @@ using System.Collections.Generic;
 namespace EnvelopeGenerator.Domain.Entities
 {
     [Table("TBSIG_DOCUMENT_RECEIVER_ELEMENT", Schema = "dbo")]
-    public class Signature : ISignature, IHasReceiver, IHasAddedWhen, IUpdateAuditable
+    public class DocReceiverElement : IDocReceiverElement, IHasReceiver, IHasAddedWhen, IUpdateAuditable
     {
-        public Signature()
+        public DocReceiverElement()
         {
             // TODO: * Check the Form App and remove the default value
 #if NETFRAMEWORK
@@ -126,5 +126,33 @@ namespace EnvelopeGenerator.Domain.Entities
         [NotMapped]
         public double Left => Math.Round(X, 5);
 #endif
+
+        [Column("FULL_NAME", TypeName = "nvarchar(100)")]
+        public string
+#if nullable
+        ?
+# endif
+            FullName { get; set; }
+
+        [Column("POSITION", TypeName = "nvarchar(100)")]
+        public string
+#if nullable
+        ?
+#endif
+            Position { get; set; }
+
+        [Column("PLACE", TypeName = "nvarchar(100)")]
+        public string
+#if nullable
+        ?
+#endif
+            Place { get; set; }
+
+        [Column("INK", TypeName = "varbinary(MAX)")]
+        public byte[]
+#if nullable
+        ?
+#endif
+            Ink { get; set; }
     }
 }

EnvelopeGenerator.Domain/Entities/Document.cs

@@ -18,7 +18,7 @@ namespace EnvelopeGenerator.Domain.Entities
         public Document()
         {
 #if NETFRAMEWORK
-            Elements = Enumerable.Empty<Signature>().ToList();
+            Elements = Enumerable.Empty<DocReceiverElement>().ToList();
 #endif
         }
 
@@ -60,7 +60,7 @@ namespace EnvelopeGenerator.Domain.Entities
             FileNameOriginal { get; set; }
         #endregion
 
-        public virtual List<Signature>
+        public virtual List<DocReceiverElement>
 #if nullable
             ?
 #endif

EnvelopeGenerator.Domain/Entities/ElementAnnotation.cs

@@ -76,7 +76,7 @@ namespace EnvelopeGenerator.Domain.Entities
             ChangedWho { get; set; }
 
         [ForeignKey("ElementId")]
-        public virtual Signature
+        public virtual DocReceiverElement
 #if nullable
             ?
 #endif

EnvelopeGenerator.Domain/Interfaces/IDocReceiverElement.cs

@@ -1,6 +1,6 @@
 namespace EnvelopeGenerator.Domain.Interfaces
 {
-    public interface ISignature
+    public interface IDocReceiverElement
     {
         int Page { get; set; }
 

EnvelopeGenerator.Form/Controllers/FieldEditorController.vb

@@ -8,7 +8,7 @@ Public Class FieldEditorController
     Inherits BaseController
 
     Private ReadOnly Document As Document
-    Public Property Elements As New List(Of Signature)
+    Public Property Elements As New List(Of DocReceiverElement)
 
     Public Class ElementInfo
         Public ReceiverId As Integer
@@ -36,7 +36,7 @@ Public Class FieldEditorController
         }
     End Function
 
-    Private Function GetElementByPosition(pAnnotation As AnnotationStickyNote, pPage As Integer, pReceiverId As Integer) As Signature
+    Private Function GetElementByPosition(pAnnotation As AnnotationStickyNote, pPage As Integer, pReceiverId As Integer) As DocReceiverElement
         Dim oElement = Elements.
             Where(Function(e)
                       Return e.Left = CSng(Math.Round(pAnnotation.Left, 5)) And
@@ -47,12 +47,12 @@ Public Class FieldEditorController
         Return oElement
     End Function
 
-    Private Function GetElementByGuid(pGuid As Integer) As Signature
+    Private Function GetElementByGuid(pGuid As Integer) As DocReceiverElement
         Dim oElement = Elements.Where(Function(e) pGuid = e.Id).SingleOrDefault()
         Return oElement
     End Function
 
-    Public Function GetElement(pAnnotation As AnnotationStickyNote) As Signature
+    Public Function GetElement(pAnnotation As AnnotationStickyNote) As DocReceiverElement
         Dim oInfo = GetElementInfo(pAnnotation.Tag)
 
         If oInfo.Guid = -1 Then
@@ -85,7 +85,7 @@ Public Class FieldEditorController
         Else
             Dim oInfo = GetElementInfo(pAnnotation.Tag)
 
-            Elements.Add(New Signature() With {
+            Elements.Add(New DocReceiverElement() With {
                 .ElementType = Constants.ElementType.Signature,
                 .Height = oAnnotationHeight,
                 .Width = oAnnotationWidth,
@@ -98,7 +98,7 @@ Public Class FieldEditorController
         End If
     End Sub
 
-    Public Function ClearElements(pPage As Integer, pReceiverId As Integer) As IEnumerable(Of Signature)
+    Public Function ClearElements(pPage As Integer, pReceiverId As Integer) As IEnumerable(Of DocReceiverElement)
         Return Elements.
             Where(Function(e) e.Page <> pPage And e.ReceiverId <> pReceiverId).
             ToList()
@@ -120,7 +120,7 @@ Public Class FieldEditorController
             All(Function(pResult) pResult = True)
     End Function
 
-    Public Function SaveElement(pElement As Signature) As Boolean
+    Public Function SaveElement(pElement As DocReceiverElement) As Boolean
         Try
             If pElement.Id > 0 Then
                 Return ElementModel.Update(pElement)
@@ -134,11 +134,11 @@ Public Class FieldEditorController
         End Try
     End Function
 
-    Public Function DeleteElement(pElement As Signature) As Boolean
+    Public Function DeleteElement(pElement As DocReceiverElement) As Boolean
         Try
             ' Element aus Datenbank löschen
             If ElementModel.DeleteElement(pElement) Then
-                Dim oElement = New List(Of Signature)() From {pElement}
+                Dim oElement = New List(Of DocReceiverElement)() From {pElement}
                 Elements = Elements.Except(oElement).ToList()
                 Return True
             Else

EnvelopeGenerator.Form/frmFieldEditor.vb

@@ -280,7 +280,7 @@ Partial Public Class frmFieldEditor
         End If
     End Sub
 
-    Private Sub LoadAnnotation(pElement As Signature, pReceiverId As Integer)
+    Private Sub LoadAnnotation(pElement As DocReceiverElement, pReceiverId As Integer)
         Dim oAnnotation As AnnotationStickyNote = Manager.AddStickyNoteAnnot(0, 0, 0, 0, "SIGNATUR")
         Dim oPage = pElement.Page
         Dim oReceiver = Receivers.Where(Function(r) r.Id = pReceiverId).Single()

EnvelopeGenerator.Infrastructure/DependencyInjection.cs

@@ -74,14 +74,14 @@ namespace EnvelopeGenerator.Infrastructure
             services.AddSQLExecutor<Envelope>();
             services.AddSQLExecutor<Receiver>();
             services.AddSQLExecutor<Document>();
-            services.AddSQLExecutor<Signature>();
+            services.AddSQLExecutor<DocReceiverElement>();
             services.AddSQLExecutor<DocumentStatus>();
 
             SetDapperTypeMap<Envelope>();
             SetDapperTypeMap<User>();
             SetDapperTypeMap<Receiver>();
             SetDapperTypeMap<Document>();
-            SetDapperTypeMap<Signature>();
+            SetDapperTypeMap<DocReceiverElement>();
             SetDapperTypeMap<DocumentStatus>();
 
             services.AddScoped<IEnvelopeExecutor, EnvelopeExecutor>();

EnvelopeGenerator.Infrastructure/EGDbContext.cs

@@ -45,7 +45,7 @@ public abstract class EGDbContextBase : DbContext
 
     public DbSet<Envelope> Envelopes { get; set; }
 
-    public DbSet<Signature> DocumentReceiverElements { get; set; }
+    public DbSet<DocReceiverElement> DocumentReceiverElements { get; set; }
 
     public DbSet<ElementAnnotation> DocumentReceiverElementAnnotations { get; set; }
 
@@ -154,7 +154,7 @@ public abstract class EGDbContextBase : DbContext
         #endregion EnvelopeDocument
 
         #region DocumentReceiverElement
-        modelBuilder.Entity<Signature>()
+        modelBuilder.Entity<DocReceiverElement>()
             .HasOne(dre => dre.Document)
             .WithMany(ed => ed.Elements)
             .HasForeignKey(dre => dre.DocumentId);
@@ -196,7 +196,7 @@ public abstract class EGDbContextBase : DbContext
         #endregion DocumentStatus
 
         #region Annotation
-        modelBuilder.Entity<Signature>()
+        modelBuilder.Entity<DocReceiverElement>()
             .HasMany(signature => signature.Annotations)
             .WithOne(annot => annot.Element)
             .HasForeignKey(annot => annot.ElementId);
@@ -217,7 +217,7 @@ public abstract class EGDbContextBase : DbContext
 
         // TODO: call add trigger methods with attributes and reflection
         AddTrigger<Config>();
-        AddTrigger<Signature>();
+        AddTrigger<DocReceiverElement>();
         AddTrigger<DocumentStatus>();
         AddTrigger<EmailTemplate>();
         AddTrigger<Envelope>();

EnvelopeGenerator.Infrastructure/Repositories/DocumentReceiverElementRepository.cs

@@ -6,7 +6,7 @@ using EnvelopeGenerator.Application.Common.Interfaces.Repositories;
 namespace EnvelopeGenerator.Infrastructure.Repositories;
 
 [Obsolete("Use IRepository")]
-public class DocumentReceiverElementRepository : CRUDRepository<Signature, int, EGDbContext>, IDocumentReceiverElementRepository
+public class DocumentReceiverElementRepository : CRUDRepository<DocReceiverElement, int, EGDbContext>, IDocumentReceiverElementRepository
 {
     public DocumentReceiverElementRepository(EGDbContext dbContext) : base(dbContext, dbContext.DocumentReceiverElements)
     {

EnvelopeGenerator.PdfEditor/Pdf.cs

@@ -103,7 +103,7 @@ namespace EnvelopeGenerator.PdfEditor
         #endregion
 
         public Pdf<TInputStream, TOutputStream> Background<TSignature>(IEnumerable<TSignature> signatures, double widthPx = 1.9500000000000002, double heightPx = 2.52)
-            where TSignature : ISignature
+            where TSignature : IDocReceiverElement
         {
             foreach (var signature in signatures)
                 Page(signature.Page, page =>

EnvelopeGenerator.ReceiverUI/Pages/EnvelopeViewer.razor

@@ -12,9 +12,11 @@
 @inject IOptions<PdfViewerOptions> PdfViewerOptions
 @inject IJSRuntime JSRuntime
 @inject SignatureService SignatureService
+@inject SignatureCacheService SignatureCacheService
 @inject EnvelopeGenerator.ReceiverUI.Services.AuthService AuthService
 @inject EnvelopeGenerator.ReceiverUI.Services.EnvelopeReceiverService EnvelopeReceiverService
 @inject AppVersionService AppVersion
+@inject ILogger<EnvelopeViewer> logger
 @implements IAsyncDisposable
 
 <link href="_content/DevExpress.Blazor.Themes/blazing-berry.bs5.min.css" rel="stylesheet" />
@@ -217,6 +219,20 @@
                         <div class="pdf-toolbar__divider"></div>
 
                         @if (_totalSignatures > 0) {
+                            <div class="pdf-toolbar__section">
+                                <button class="pdf-toolbar__btn pdf-toolbar__btn--signature-change @(_capturedSignature is not null ? "pdf-toolbar__btn--signature-change-active" : "")" 
+                                        disabled="@(_signedSignatures > 0)"
+                                        @onclick="HandleSignatureChangeClick" 
+                                        title="@GetSignatureButtonTitle()">
+                                    <svg xmlns="http://www.w3.org/2000/svg" width="14" height="14" fill="currentColor" viewBox="0 0 16 16">
+                                        <path d="M12.146.146a.5.5 0 0 1 .708 0l3 3a.5.5 0 0 1 0 .708l-10 10a.5.5 0 0 1-.168.11l-5 2a.5.5 0 0 1-.65-.65l2-5a.5.5 0 0 1 .11-.168l10-10zM11.207 2.5 13.5 4.793 14.793 3.5 12.5 1.207 11.207 2.5zm1.586 3L10.5 3.207 4 9.707V10h.5a.5.5 0 0 1 .5.5v.5h.5a.5.5 0 0 1 .5.5v.5h.293l6.5-6.5zm-9.761 5.175-.106.106-1.528 3.821 3.821-1.528.106-.106A.5.5 0 0 1 5 12.5V12h-.5a.5.5 0 0 1-.5-.5V11h-.5a.5.5 0 0 1-.468-.325z"/>
+                                    </svg>
+                                    <span class="pdf-toolbar__btn-text">Unterschrift</span>
+                                </button>
+                            </div>
+
+                            <div class="pdf-toolbar__divider"></div>
+
                             <div class="pdf-toolbar__section pdf-toolbar__signature-nav">
                                 <button class="pdf-toolbar__btn pdf-toolbar__btn--signature-nav" 
                                         @onclick="GoToPreviousSignature" 
@@ -503,7 +519,7 @@ EnvelopeReceiverDto? _envelopeReceiver;
 int _totalSignatures = 0;
 int _signedSignatures = 0;
 int _unsignedSignatures = 0;
-int _currentSignatureIndex = 0;  // Şu an hangi imzada (1-based)
+int _currentSignatureIndex = 0;  // Current signature index (1-based)
 
 // Signature state
 SignatureCaptureDto? _capturedSignature;
@@ -563,10 +579,34 @@ const int MaxThumbnailWidth = 400;
 
             await JSRuntime.InvokeVoidAsync("console.log", "Loaded signatures:", _signatures);
 
-            // Open signature popup on page load
+            // Try to load cached signature first
-            _activeSignatureTab = SignatureTabDraw;
+            try
-            _signaturePopupVisible = true;
+            {
-            _popupValidationMessage = null;
+                var cachedSignature = await SignatureCacheService.GetSignatureAsync(EnvelopeKey);
+                if (cachedSignature is not null)
+                {
+                    _capturedSignature = cachedSignature;
+                    _signerFullName = cachedSignature.FullName;
+                    _signerPosition = cachedSignature.Position;
+                    _signaturePlace = cachedSignature.Place;
+                    _signaturePopupVisible = false;
+                    
+                    logger.LogInformation("Cached signature loaded for envelope {EnvelopeKey}", EnvelopeKey);
+                }
+                else
+                {
+                    _activeSignatureTab = SignatureTabDraw;
+                    _signaturePopupVisible = true;
+                    _popupValidationMessage = null;
+                }
+            }
+            catch (Exception ex)
+            {
+                logger.LogWarning(ex, "Failed to load cached signature, showing popup");
+                _activeSignatureTab = SignatureTabDraw;
+                _signaturePopupVisible = true;
+                _popupValidationMessage = null;
+            }
 
         } catch (Exception ex) {
             _errorMessage = $"Fehler: {ex.Message}";
@@ -777,7 +817,7 @@ const int MaxThumbnailWidth = 400;
             _totalSignatures = state.Total;
             _signedSignatures = state.Signed;
             _unsignedSignatures = state.Unsigned;
-            _currentSignatureIndex = state.CurrentIndex;  // Şu an hangi imzada
+            _currentSignatureIndex = state.CurrentIndex;  // Current signature
             await InvokeAsync(StateHasChanged);
         } catch {
             // Ignore errors during counter update
@@ -799,15 +839,52 @@ const int MaxThumbnailWidth = 400;
 
     record SignatureNavState(int Total, int Signed, int Unsigned, int CurrentIndex, bool CanGoPrev, bool CanGoNext);
 
+    string GetSignatureButtonTitle()
+    {
+        if (_signedSignatures > 0)
+            return "Unterschrift ist gesperrt – bitte Seite neu laden, um zu ändern";
+        
+        return _capturedSignature is not null 
+            ? "Unterschrift ändern" 
+            : "Unterschrift erstellen";
+    }
+
+    void HandleSignatureChangeClick()
+    {
+        // If any signature is applied, button is disabled - this won't be called
+        // But just in case, do nothing
+        if (_signedSignatures > 0)
+            return;
+        
+        // No signatures applied - open popup normally
+        OpenSignaturePopup();
+    }
+
     // Signature popup methods
     void OpenSignaturePopup() {
+        // Open popup with current signature (edit mode)
         _activeSignatureTab = SignatureTabDraw;
         _signaturePopupVisible = true;
         _popupValidationMessage = null;
+        
+        // Load current signature info into form fields
+        if (_capturedSignature is not null)
+        {
+            _signerFullName = _capturedSignature.FullName;
+            _signerPosition = _capturedSignature.Position;
+            _signaturePlace = _capturedSignature.Place;
+        }
     }
 
     async Task OnPopupShownAsync() {
         await InitializeActiveSignatureTabAsync();
+        
+        // If there's an existing signature and we're on draw tab, load it to canvas
+        if (_capturedSignature is not null && _activeSignatureTab == SignatureTabDraw)
+        {
+            await Task.Delay(100); // Wait for canvas to be ready
+            await JSRuntime.InvokeVoidAsync("receiverSignature.loadExistingSignature", DrawCanvasId, _capturedSignature.DataUrl);
+        }
     }
 
     async Task SetSignatureTabAsync(string tab) {
@@ -881,6 +958,22 @@ const int MaxThumbnailWidth = 400;
         };
         _signaturePopupVisible = false;
         
+        // Save to cache (fire-and-forget, ignore errors)
+        if (!string.IsNullOrWhiteSpace(EnvelopeKey))
+        {
+            _ = Task.Run(async () =>
+            {
+                try
+                {
+                    await SignatureCacheService.SaveSignatureAsync(EnvelopeKey, _capturedSignature);
+                }
+                catch
+                {
+                    // Ignore cache errors
+                }
+            });
+        }
+        
         await InvokeAsync(StateHasChanged);
         Console.WriteLine($"Signature saved: {_signerFullName}, {_signaturePlace}");
     }

EnvelopeGenerator.ReceiverUI/Program.cs

@@ -16,12 +16,13 @@ builder.Services.Configure<ApiOptions>(opts =>
 builder.Configuration.GetSection(ApiOptions.SectionName).Bind(opts));
 builder.Services.Configure<PdfViewerOptions>(opts =>
 builder.Configuration.GetSection(PdfViewerOptions.SectionName).Bind(opts));
-builder.Services.AddScoped<EnvelopeGenerator.ReceiverUI.Services.DocumentService>();
+builder.Services.AddScoped<DocumentService>();
-builder.Services.AddScoped<EnvelopeGenerator.ReceiverUI.Services.AuthService>();
+builder.Services.AddScoped<AuthService>();
-builder.Services.AddScoped<EnvelopeGenerator.ReceiverUI.Services.AnnotationService>();
+builder.Services.AddScoped<AnnotationService>();
-builder.Services.AddScoped<EnvelopeGenerator.ReceiverUI.Services.EnvelopeReceiverService>();
+builder.Services.AddScoped<EnvelopeReceiverService>();
-builder.Services.AddScoped<EnvelopeGenerator.ReceiverUI.Services.SignatureService>();
+builder.Services.AddScoped<SignatureService>();
-builder.Services.AddSingleton<EnvelopeGenerator.ReceiverUI.Services.AppVersionService>();
+builder.Services.AddScoped<SignatureCacheService>();
+builder.Services.AddSingleton<AppVersionService>();
 
 builder.Services.AddDevExpressWebAssemblyBlazorReportViewer();
 builder.Services.AddDevExpressWebAssemblyBlazorPdfViewer();

EnvelopeGenerator.ReceiverUI/Services/SignatureCacheService.cs

@@ -0,0 +1,67 @@
+using System.Net.Http.Json;
+using Microsoft.Extensions.Options;
+using EnvelopeGenerator.ReceiverUI.Options;
+using EnvelopeGenerator.ReceiverUI.Models;
+
+namespace EnvelopeGenerator.ReceiverUI.Services;
+
+/// <summary>
+/// Client service for managing cached signatures via API.
+/// </summary>
+public class SignatureCacheService(HttpClient http, IOptions<ApiOptions> apiOptions)
+{
+    private readonly ApiOptions _api = apiOptions.Value;
+
+    public async Task SaveSignatureAsync(
+        string envelopeKey,
+        SignatureCaptureDto signature,
+        CancellationToken cancel = default)
+    {
+        var response = await http.PostAsJsonAsync(
+            $"{_api.BaseUrl}/api/Cache/SignatureCapture/{Uri.EscapeDataString(envelopeKey)}",
+            signature,
+            cancel);
+
+        if (!response.IsSuccessStatusCode)
+        {
+            var error = await response.Content.ReadAsStringAsync(cancel);
+            throw new HttpRequestException($"Failed to cache signature: {response.StatusCode} - {error}");
+        }
+    }
+
+    public async Task<SignatureCaptureDto?> GetSignatureAsync(
+        string envelopeKey,
+        CancellationToken cancel = default)
+    {
+        var response = await http.GetAsync(
+            $"{_api.BaseUrl}/api/Cache/SignatureCapture/{Uri.EscapeDataString(envelopeKey)}",
+            cancel);
+
+        if (response.StatusCode == System.Net.HttpStatusCode.NotFound)
+            return null;
+
+        if (!response.IsSuccessStatusCode)
+        {
+            var error = await response.Content.ReadAsStringAsync(cancel);
+            throw new HttpRequestException($"Failed to retrieve signature: {response.StatusCode} - {error}");
+        }
+
+        return await response.Content.ReadFromJsonAsync<SignatureCaptureDto>(cancellationToken: cancel);
+    }
+
+    public async Task DeleteSignatureAsync(
+        string envelopeKey,
+        CancellationToken cancel = default)
+    {
+        var response = await http.DeleteAsync(
+            $"{_api.BaseUrl}/api/Cache/SignatureCapture/{Uri.EscapeDataString(envelopeKey)}",
+            cancel);
+
+        if (!response.IsSuccessStatusCode)
+        {
+            var error = await response.Content.ReadAsStringAsync(cancel);
+            throw new HttpRequestException($"Failed to delete signature: {response.StatusCode} - {error}");
+        }
+    }
+}
+

EnvelopeGenerator.ReceiverUI/wwwroot/css/envelope-viewer.css

@@ -484,6 +484,68 @@ body.resizing {
     color: white;
 }
 
+/* Success Button Styles (Signature Created) */
+.pdf-toolbar__btn--success {
+    background: linear-gradient(135deg, rgba(16, 185, 129, 0.1) 0%, rgba(5, 150, 105, 0.1) 100%);
+    border-color: rgba(16, 185, 129, 0.3);
+    color: #059669;
+}
+
+.pdf-toolbar__btn--success:hover:not(:disabled) {
+    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
+    border-color: transparent;
+    color: white;
+    transform: translateY(-1px);
+    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3);
+}
+
+.pdf-toolbar__btn--success svg {
+    transition: color 0.2s ease;
+}
+
+.pdf-toolbar__btn--success:hover:not(:disabled) svg {
+    color: white;
+}
+
+/* Signature Change Button */
+.pdf-toolbar__btn--signature-change {
+    display: flex;
+    align-items: center;
+    gap: 0.375rem;
+    min-width: auto;
+    padding: 0.5rem 0.75rem;
+    background: linear-gradient(135deg, rgba(126, 34, 206, 0.05) 0%, rgba(42, 82, 152, 0.05) 100%);
+    border: 1px solid rgba(126, 34, 206, 0.2);
+    color: #7e22ce;
+}
+
+.pdf-toolbar__btn--signature-change:hover:not(:disabled) {
+    background: linear-gradient(135deg, rgba(126, 34, 206, 0.1) 0%, rgba(42, 82, 152, 0.1) 100%);
+    border-color: rgba(126, 34, 206, 0.4);
+}
+
+.pdf-toolbar__btn--signature-change-active {
+    background: linear-gradient(135deg, rgba(16, 185, 129, 0.08) 0%, rgba(5, 150, 105, 0.08) 100%);
+    border-color: rgba(16, 185, 129, 0.25);
+    color: #059669;
+}
+
+.pdf-toolbar__btn--signature-change-active:hover:not(:disabled) {
+    background: linear-gradient(135deg, rgba(16, 185, 129, 0.12) 0%, rgba(5, 150, 105, 0.12) 100%);
+    border-color: rgba(16, 185, 129, 0.35);
+}
+
+.pdf-toolbar__btn--signature-change:disabled {
+    opacity: 0.5;
+    cursor: not-allowed;
+}
+
+.pdf-toolbar__btn-text {
+    font-size: 0.813rem;
+    font-weight: 600;
+    white-space: nowrap;
+}
+
 .pdf-frame {
     background: white;
     border-radius: 16px;

EnvelopeGenerator.ReceiverUI/wwwroot/js/pdf-viewer.js

@@ -489,7 +489,7 @@ window.pdfViewer = {
      * @returns {object} { total, signed, unsigned, currentIndex, canGoPrev, canGoNext }
      */
     getSignatureNavState() {
-        // Global imza listesi yoksa bo? state d<>n
+        // Return empty state if global signature list is empty
         if (!this._allSignatures || this._allSignatures.length === 0) {
             return {
                 total: 0,
@@ -501,25 +501,26 @@ window.pdfViewer = {
             };
         }
         
-        // T<>M sayfalardaki imzalar? say (database'den gelen global liste)
-        const total = this._allSignatures.length;           // Global: Toplam imza say?s?
-        const signed = this.appliedSignatures.length;       // ?mzalananlar
-        const unsigned = total - signed;                    // Hesaplanan: ?mzalanmayanlar
         
-        // Mevcut görüntülenen imzanın sıra numarasını bul
+        // Count signatures across ALL pages (from database global list)
+        const total = this._allSignatures.length;           // Global: Total signature count
+        const signed = this.appliedSignatures.length;       // Signed signatures
+        const unsigned = total - signed;                    // Calculated: Unsigned signatures
+        
+        // Find the current viewed signature index
         let currentIndex = 0;
         if (this._lastViewedSignatureId) {
             const index = this._allSignatures.findIndex(s => s.id === this._lastViewedSignatureId);
-            currentIndex = index !== -1 ? index + 1 : 0;  // 1-based index (kullanıcıya göstermek için)
+            currentIndex = index !== -1 ? index + 1 : 0;  // 1-based index (for user display)
         }
                 
         return {
             total: total,
             signed: signed,
             unsigned: unsigned,
-            currentIndex: currentIndex,  // Şu an hangi imzada (1-5 arası)
+            currentIndex: currentIndex,  // Current signature index (1-5 range)
-            canGoPrev: total > 0,           // Her zaman aktif (e?er imza varsa)
+            canGoPrev: total > 0,           // Always active (if signatures exist)
-            canGoNext: total > 0            // Her zaman aktif (e?er imza varsa)
+            canGoNext: total > 0            // Always active (if signatures exist)
         };
     },
 
@@ -529,63 +530,64 @@ window.pdfViewer = {
      * Cross-page navigation: searches ALL pages for next unsigned signature.
      */
     async goToNextSignature(dotNetRef) {
-        // Global imza listesi yoksa <20>?k
+        // Exit if no global signature list
         if (!this._allSignatures || this._allSignatures.length === 0) {
             return false;
         }
 
-        // Mevcut g<>r<EFBFBD>nt<6E>lenen imzan?n index'ini bul
+        // Find current displayed signature's index
         let currentIndex = -1;
         if (this._lastViewedSignatureId) {
             currentIndex = this._allSignatures.findIndex(s => s.id === this._lastViewedSignatureId);
         }
         
-        // Bir sonraki imzay? al (imzalanm?? olup olmad???na bakmadan)
+        // Get next signature (regardless of signed status)
         let nextIndex = currentIndex + 1;
         
-        // Sonsuz d<>ng<6E>: Son imzadaysa ilk imzaya d<>n
+        // Infinite loop: If at last signature, return to first
         if (nextIndex >= this._allSignatures.length) {
-            nextIndex = 0;  // ?lk imzaya d<>n
+            nextIndex = 0;  // Return to first signature
         }
         
         const nextSignature = this._allSignatures[nextIndex];
 
-        // Farkl? sayfadaysa sayfa de?i?tir
+        // Change page if signature is on different page
         if (nextSignature.page !== this.pageNum) {
-            // Sayfa de?i?tir
+            // Change page
             this.pageNum = nextSignature.page;
             this.queueRenderPage(this.pageNum);
             
-            // Render tamamlanana kadar bekle
+            // Wait until render completes
             let waitCount = 0;
             while (this.pageRendering && waitCount < 20) {
                 await new Promise(resolve => setTimeout(resolve, 100));
                 waitCount++;
             }
             
-            // Blazor'a haber ver - signature butonlar?n? yeniden ?iz
+            // Notify Blazor - re-render signature buttons
             if (dotNetRef) {
                 await dotNetRef.invokeMethodAsync('OnPageChangedBySignatureNav', this.pageNum);
             }
             
-            // Butonlar?n DOM'a eklenmesini bekle
+            // Wait for buttons to be added to DOM
             await new Promise(resolve => setTimeout(resolve, 150));
         }
         
-        // Son g<>r<EFBFBD>nt<6E>lenen imzay? kaydet
+        
+        // Save last viewed signature
         this._lastViewedSignatureId = nextSignature.id;
         
-        // ?mza imzalanm?? m? kontrol et
+        // Check if signature is signed
         const isApplied = this.appliedSignatures.some(s => s.id === nextSignature.id);
         
         if (isApplied) {
-            // ?mzalanm?? - overlay container'? bul ve scroll yap
+            // Signed - find overlay container and scroll
             const container = document.querySelector(`.applied-signature[data-signature-id="${nextSignature.id}"]`);
             if (container) {
                 this.scrollToElement(container);
             }
         } else {
-            // ?mzalanmam?? - butonu bul ve scroll yap
+            // Unsigned - find button and scroll
             const button = this.signatureButtons.find(btn => 
                 parseInt(btn.getAttribute('data-signature-id')) === nextSignature.id
             );
@@ -594,7 +596,7 @@ window.pdfViewer = {
             }
         }
 
-        // Counter'? g<>ncelle (Blazor'a bildir)
+        // Update counter (notify Blazor)
         if (dotNetRef) {
             dotNetRef.invokeMethodAsync('OnSignatureNavChanged');
         }
@@ -611,58 +613,58 @@ window.pdfViewer = {
             return false;
         }
 
-        // Mevcut g<>r<EFBFBD>nt<6E>lenen imzan?n index'ini bul
+        // Find current displayed signature's index
-        let currentIndex = this._allSignatures.length;  // Varsay?lan: son imzadan sonra
+        let currentIndex = this._allSignatures.length;  // Default: after last signature
         if (this._lastViewedSignatureId) {
             currentIndex = this._allSignatures.findIndex(s => s.id === this._lastViewedSignatureId);
         }
         
-        // Bir <20>nceki imzay? al
+        // Get previous signature
         let prevIndex = currentIndex - 1;
         
-        // Sonsuz d<>ng<6E>: ?lk imzadaysa son imzaya git
+        // Infinite loop: If at first signature, go to last
         if (prevIndex < 0) {
-            prevIndex = this._allSignatures.length - 1;  // Son imzaya git
+            prevIndex = this._allSignatures.length - 1;  // Go to last signature
         }
         
         const prevSignature = this._allSignatures[prevIndex];
         
         // Change page if needed
         if (prevSignature.page !== this.pageNum) {
-            // Sayfa de?i?tir
+            // Change page
             this.pageNum = prevSignature.page;
             this.queueRenderPage(this.pageNum);
             
-            // Render tamamlanana kadar bekle
+            // Wait until render completes
             let waitCount = 0;
             while (this.pageRendering && waitCount < 20) {
                 await new Promise(resolve => setTimeout(resolve, 100));
                 waitCount++;
             }
             
-            // Blazor'a haber ver - signature butonlar?n? yeniden <20>iz
+            // Notify Blazor - re-render signature buttons
             if (dotNetRef) {
                 await dotNetRef.invokeMethodAsync('OnPageChangedBySignatureNav', this.pageNum);
             }
             
-            // DOM g<>ncellenmesini bekle
+            // Wait for DOM update
             await new Promise(resolve => setTimeout(resolve, 150));
         }
 
-        // Son g<>r<EFBFBD>nt<6E>lenen imzay? kaydet
+        // Save last viewed signature
         this._lastViewedSignatureId = prevSignature.id;
         
-        // ?mza imzalanm?? m? kontrol et
+        // Check if signature is signed
         const isApplied = this.appliedSignatures.some(s => s.id === prevSignature.id);
         
         if (isApplied) {
-            // ?mzalanm?? - overlay container'? bul ve scroll yap
+            // Signed - find overlay container and scroll
             const container = document.querySelector(`.applied-signature[data-signature-id="${prevSignature.id}"]`);
             if (container) {
                 this.scrollToElement(container);
             }
         } else {
-            // ?mzalanmam?? - butonu bul ve scroll yap
+            // Unsigned - find button and scroll
             const button = this.signatureButtons.find(btn => 
                 parseInt(btn.getAttribute('data-signature-id')) === prevSignature.id
             );
@@ -1070,8 +1072,8 @@ window.pdfViewer = {
 
             // Text information container
             const infoContainer = document.createElement('div');
-            infoContainer.className = 'signature-info-text';  // ✅ Class ekle (querySelector için)
+            infoContainer.className = 'signature-info-text';  // ✅ Add class (for querySelector)
-            infoContainer.setAttribute('data-base-font-size', '9');  // ✅ Base font size sakla
+            infoContainer.setAttribute('data-base-font-size', '9');  // ✅ Store base font size
             infoContainer.style.fontSize = '9px';
             infoContainer.style.lineHeight = '1.4';
             infoContainer.style.color = '#495057';

EnvelopeGenerator.ReceiverUI/wwwroot/js/receiver-signature.js

@@ -316,6 +316,23 @@ window.receiverSignature = (() => {
     function getTypedDataUrl(id) { const c = document.getElementById(id); const s = typedSignatures.get(id); return (c && s && s.hasSignature) ? c.toDataURL('image/png') : null; }
     function getImageDataUrl(id) { const c = document.getElementById(id); const s = imageSignatures.get(id); return (c && s && s.hasSignature) ? c.toDataURL('image/png') : null; }
 
+    function loadExistingSignature(canvasId, dataUrl) {
+        const canvas = document.getElementById(canvasId);
+        const state = pads.get(canvasId);
+        if (!canvas || !state || !dataUrl) return;
+
+        const ctx = canvas.getContext('2d');
+        const img = new Image();
+        
+        img.onload = () => {
+            _clear(canvas);
+            ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
+            state.hasSignature = true;
+        };
+        
+        img.src = dataUrl;
+    }
+
     // ?? Public API ??????????????????????????????????????????????????????????
     return {
         startTyped:                  startTyped,
@@ -329,6 +346,8 @@ window.receiverSignature = (() => {
         renderTypedSignature:        renderTypedSignature,
         getDataUrl:                  getDataUrl,
         getTypedDataUrl:             getTypedDataUrl,
-        getImageDataUrl:             getImageDataUrl
+        getImageDataUrl:             getImageDataUrl,
+        loadExistingSignature:       loadExistingSignature
     };
 })();
+

EnvelopeGenerator.Tests/Application/DocSignedNotificationTests.cs

@@ -2,6 +2,7 @@
 using DigitalData.Core.Abstraction.Application.Repository;
 using DigitalData.Core.Infrastructure;
 using DigitalData.EmailProfilerDispatcher.Abstraction.Entities;
+using EnvelopeGenerator.Application.Common.Dto;
 using EnvelopeGenerator.Application.Common.Dto.EnvelopeReceiver;
 using EnvelopeGenerator.Application.Common.Notifications.DocSigned;
 using EnvelopeGenerator.Application.Common.Notifications.DocSigned.Handlers;
@@ -53,7 +54,7 @@ public class DocSignedNotificationTests : TestBase
 
         var annots = Services.GetRequiredService<PsPdfKitAnnotation>();
 
-        var docSignedNtf = envRcvDto.ToDocSignedNotification(annots);
+        var docSignedNtf = new DocSignedNotification { EnvelopeReceiver = envRcvDto, PsPdfKitAnnotation = annots };
 
         var sendSignedMailHandler = Host.Services.GetRequiredService<SendSignedMailHandler>();
 

EnvelopeGenerator.Web/Controllers/AnnotationController.cs

@@ -1,8 +1,10 @@
 using DigitalData.Core.Abstraction.Application.DTO;
 using DigitalData.Core.Exceptions;
+using EnvelopeGenerator.Application.Common.Dto;
 using EnvelopeGenerator.Application.Common.Extensions;
 using EnvelopeGenerator.Application.Common.Interfaces.Services;
 using EnvelopeGenerator.Application.Common.Notifications.DocSigned;
+using EnvelopeGenerator.Application.Common.Notifications.RemoveSignature;
 using EnvelopeGenerator.Application.EnvelopeReceivers.Queries;
 using EnvelopeGenerator.Application.Histories.Queries;
 using EnvelopeGenerator.Domain.Constants;
@@ -45,6 +47,7 @@ public class AnnotationController : ControllerBase
 
     [Authorize(Roles = Role.ReceiverFull)]
     [HttpPost]
+    [Obsolete("This notification is deprecated. Use Signature.Commands.SignCommand instead.")]
     public async Task<IActionResult> CreateOrUpdate([FromBody] PsPdfKitAnnotation? psPdfKitAnnotation = null, CancellationToken cancel = default)
     {
         // get claims
@@ -69,12 +72,24 @@ public class AnnotationController : ControllerBase
         else if (er.Envelope.IsReadAndSign() && await _mediator.AnyHistoryAsync(uuid, new[] { EnvelopeStatus.EnvelopeRejected, EnvelopeStatus.DocumentRejected }, cancel))
             return Problem(statusCode: 423);
 
-        var docSignedNotification = await _mediator
+        var envelopeReceiverDto = await _mediator.ReadEnvelopeReceiverAsync(uuid, signature, cancel);
-            .ReadEnvelopeReceiverAsync(uuid, signature, cancel)
+        var docSignedNotification = envelopeReceiverDto is not null
-            .ToDocSignedNotification(psPdfKitAnnotation)
+            ? new DocSignedNotification { EnvelopeReceiver = envelopeReceiverDto, PsPdfKitAnnotation = psPdfKitAnnotation }
-            ?? throw new NotFoundException("Envelope receiver is not found.");
+            : throw new NotFoundException("Envelope receiver is not found.");
 
-        await _mediator.PublishSafely(docSignedNotification, cancel);
+        try
+        {
+            await _mediator.Publish(docSignedNotification, cancel);
+        }
+        catch (Exception)
+        {
+            await _mediator.Publish(new RemoveSignatureNotification()
+            {
+                EnvelopeId = docSignedNotification.EnvelopeReceiver.EnvelopeId,
+                ReceiverId = docSignedNotification.EnvelopeReceiver.ReceiverId
+            }, cancel);
+            throw;
+        }
 
         await HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
 

EnvelopeGenerator.Web/Controllers/Test/TestDocumentReceiverElementController.cs

@@ -5,7 +5,7 @@ using EnvelopeGenerator.Application.Common.Interfaces.Services;
 namespace EnvelopeGenerator.Web.Controllers.Test;
 
 [Obsolete("Use MediatR")]
-public class TestDocumentReceiverElementController : TestControllerBase<IDocumentReceiverElementService, SignatureDto, Signature, int>
+public class TestDocumentReceiverElementController : TestControllerBase<IDocumentReceiverElementService, DocReceiverElementDto, DocReceiverElement, int>
 {
     public TestDocumentReceiverElementController(ILogger<TestDocumentReceiverElementController> logger, IDocumentReceiverElementService service) : base(logger, service)
     {