diff --git a/EnvelopeGenerator.Application/Common/Dto/EnvelopeDto.cs b/EnvelopeGenerator.Application/Common/Dto/EnvelopeDto.cs
index 0a1ce4a4..a1fd893b 100644
--- a/EnvelopeGenerator.Application/Common/Dto/EnvelopeDto.cs
+++ b/EnvelopeGenerator.Application/Common/Dto/EnvelopeDto.cs
@@ -84,7 +84,7 @@ public record EnvelopeDto : IEnvelope
     /// <summary>
     /// 
     /// </summary>
-    public int? CertificationType { get; set; }
+    public CertificationType? CertificationType { get; set; }
 
     /// <summary>
     /// 
diff --git a/EnvelopeGenerator.Application/Common/Dto/EnvelopeTypeDto.cs b/EnvelopeGenerator.Application/Common/Dto/EnvelopeTypeDto.cs
index cb2e4578..1246402b 100644
--- a/EnvelopeGenerator.Application/Common/Dto/EnvelopeTypeDto.cs
+++ b/EnvelopeGenerator.Application/Common/Dto/EnvelopeTypeDto.cs
@@ -1,4 +1,6 @@
-namespace EnvelopeGenerator.Application.Common.Dto;
+using EnvelopeGenerator.Domain.Constants;
+
+namespace EnvelopeGenerator.Application.Common.Dto;
 
 /// <summary>
 /// Data Transfer Object representing a type of envelope with its configuration settings.
@@ -28,7 +30,7 @@ public class EnvelopeTypeDto
     /// <summary>
     /// Gets or sets the certification type identifier.
     /// </summary>
-    public int? CertificationType { get; set; }
+    public CertificationType? CertificationType { get; set; }
 
     /// <summary>
     /// Gets or sets a value indicating whether an access code is required.
diff --git a/EnvelopeGenerator.Application/EnvelopeTypes/Queries/ReadEnvelopeTypesQuery.cs b/EnvelopeGenerator.Application/EnvelopeTypes/Queries/ReadEnvelopeTypesQuery.cs
index 4196dae4..232db96a 100644
--- a/EnvelopeGenerator.Application/EnvelopeTypes/Queries/ReadEnvelopeTypesQuery.cs
+++ b/EnvelopeGenerator.Application/EnvelopeTypes/Queries/ReadEnvelopeTypesQuery.cs
@@ -45,7 +45,7 @@ public class ReadEnvelopeTypesQueryHandler : IRequestHandler<ReadEnvelopeTypesQu
                 Title = t.Title ?? string.Empty,
                 Language = string.IsNullOrWhiteSpace(t.Language) ? "de-DE" : t.Language,
                 ExpiresDays = t.ExpiresDays,
-                CertificationType = (int?)t.CertificationType,
+                CertificationType = t.CertificationType,
                 UseAccessCode = t.UseAccessCode,
                 FinalEmailToCreator = (int?)t.FinalEmailToCreator,
                 FinalEmailToReceivers = (int?)t.FinalEmailToReceivers,
diff --git a/EnvelopeGenerator.Application/Envelopes/Commands/CreateEnvelopeCommand.cs b/EnvelopeGenerator.Application/Envelopes/Commands/CreateEnvelopeCommand.cs
index dfaf7917..28f4ea86 100644
--- a/EnvelopeGenerator.Application/Envelopes/Commands/CreateEnvelopeCommand.cs
+++ b/EnvelopeGenerator.Application/Envelopes/Commands/CreateEnvelopeCommand.cs
@@ -1,5 +1,6 @@
 using EnvelopeGenerator.Application.Common.Dto;
 using EnvelopeGenerator.Application.Common.Interfaces.SQLExecutor;
+using EnvelopeGenerator.Domain.Constants;
 using MediatR;
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
@@ -35,7 +36,7 @@ public record CreateEnvelopeCommand : IRequest<EnvelopeDto?>
     /// <summary>
     /// Zertifizierungstyp fuer den Signaturprozess.
     /// </summary>
-    public int? CertificationType { get; set; }
+    public CertificationType? CertificationType { get; set; }
 
     /// <summary>
     /// Finale E-Mail-Einstellung fuer den Ersteller.
diff --git a/EnvelopeGenerator.Application/Envelopes/Commands/CreateEnvelopeCommandHandler.cs b/EnvelopeGenerator.Application/Envelopes/Commands/CreateEnvelopeCommandHandler.cs
index 6322837c..6e7386a4 100644
--- a/EnvelopeGenerator.Application/Envelopes/Commands/CreateEnvelopeCommandHandler.cs
+++ b/EnvelopeGenerator.Application/Envelopes/Commands/CreateEnvelopeCommandHandler.cs
@@ -267,10 +267,10 @@ public class CreateEnvelopeCommandHandler : IRequestHandler<CreateEnvelopeComman
             EnvelopeTypeId: request.EnvelopeTypeId ?? existing?.EnvelopeTypeId,
             Language: ResolveLanguage(request.Language, selectedType?.Language, existing?.Language),
             UseAccessCode: useAccessCode,
-            CertificationType: NormalizeCertificationType(request.CertificationType
-                ?? (int?)selectedType?.CertificationType
+            CertificationType: request.CertificationType
+                ?? selectedType?.CertificationType
                 ?? existing?.CertificationType
-                ?? (int)CertificationType.AdvancedElectronicSignature),
+                ?? CertificationType.AdvancedElectronicSignature,
             FinalEmailToCreator: request.FinalEmailToCreator
                 ?? (int?)selectedType?.FinalEmailToCreator
                 ?? existing?.FinalEmailToCreator
@@ -316,18 +316,11 @@ public class CreateEnvelopeCommandHandler : IRequestHandler<CreateEnvelopeComman
         return "de-DE";
     }
 
-    private static int NormalizeCertificationType(int value)
-    {
-        return value == 2
-            ? 2
-            : (int)CertificationType.AdvancedElectronicSignature;
-    }
-
     private sealed record EnvelopeSettings(
         int? EnvelopeTypeId,
         string Language,
         bool UseAccessCode,
-        int CertificationType,
+        CertificationType CertificationType,
         int FinalEmailToCreator,
         int FinalEmailToReceivers,
         bool SendReminderEmails,
diff --git a/EnvelopeGenerator.Domain/Entities/Envelope.cs b/EnvelopeGenerator.Domain/Entities/Envelope.cs
index ba2f0719..dbeb2616 100644
--- a/EnvelopeGenerator.Domain/Entities/Envelope.cs
+++ b/EnvelopeGenerator.Domain/Entities/Envelope.cs
@@ -30,7 +30,7 @@ namespace EnvelopeGenerator.Domain.Entities
             SendReminderEmails = false;
             FirstReminderDays = 0;
             ReminderIntervalDays = 0;
-            CertificationType = (int)Constants.CertificationType.AdvancedElectronicSignature;
+            CertificationType = Constants.CertificationType.AdvancedElectronicSignature;
             UseAccessCode = false;
             Documents = Enumerable.Empty<Document>().ToList();
             Histories = Enumerable.Empty<History>().ToList();
@@ -111,7 +111,7 @@ namespace EnvelopeGenerator.Domain.Entities
         public bool ReadOnly => this.IsReadAndConfirm();
 
         [Column("CERTIFICATION_TYPE")]
-        public int? CertificationType { get; set; }
+        public CertificationType? CertificationType { get; set; }
 
         [Column("USE_ACCESS_CODE")]
         public bool? UseAccessCode { get; set; }
diff --git a/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Components/Sender/CreateEnvelopeWizardPopup.razor b/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Components/Sender/CreateEnvelopeWizardPopup.razor
index 0c512931..1b1242c6 100644
--- a/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Components/Sender/CreateEnvelopeWizardPopup.razor
+++ b/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Components/Sender/CreateEnvelopeWizardPopup.razor
@@ -420,7 +420,7 @@
     private string _language = "de-DE";
     private bool _useAccessCode;
     private bool _tfaEnabled;
-    private int _certificationType = (int)CertificationType.AdvancedElectronicSignature;
+    private CertificationType _certificationType = CertificationType.AdvancedElectronicSignature;
     private int _finalEmailToCreator = (int)FinalEmailType.No;
     private int _finalEmailToReceivers = (int)FinalEmailType.No;
     private bool _sendReminderEmails;
@@ -1025,7 +1025,7 @@
             _useAccessCode = true;
 
         if (envelopeType.CertificationType.HasValue)
-            _certificationType = NormalizeCertificationType(envelopeType.CertificationType.Value);
+            _certificationType = envelopeType.CertificationType.Value;
 
         if (envelopeType.FinalEmailToCreator.HasValue)
             _finalEmailToCreator = envelopeType.FinalEmailToCreator.Value;
@@ -1054,7 +1054,6 @@
     private void NormalizeSettings()
     {
         _language = string.IsNullOrWhiteSpace(_language) ? "de-DE" : _language.Trim();
-        _certificationType = NormalizeCertificationType(_certificationType);
 
         if (_tfaEnabled)
             _useAccessCode = true;
@@ -1068,13 +1067,6 @@
             _expiresWarningWhenDays = _expiresWhenDays;
     }
 
-    private static int NormalizeCertificationType(int value)
-    {
-        return value == 2
-            ? 2
-            : (int)CertificationType.AdvancedElectronicSignature;
-    }
-
     private bool ValidateSettings(out string? message)
     {
         NormalizeSettings();
@@ -1123,7 +1115,7 @@
         _language = "de-DE";
         _useAccessCode = false;
         _tfaEnabled = false;
-        _certificationType = (int)CertificationType.AdvancedElectronicSignature;
+        _certificationType = CertificationType.AdvancedElectronicSignature;
         _finalEmailToCreator = (int)FinalEmailType.No;
         _finalEmailToReceivers = (int)FinalEmailType.No;
         _sendReminderEmails = false;
diff --git a/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Components/Sender/CreateEnvelopeWizardResult.cs b/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Components/Sender/CreateEnvelopeWizardResult.cs
index c4b63ebb..6a136532 100644
--- a/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Components/Sender/CreateEnvelopeWizardResult.cs
+++ b/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Components/Sender/CreateEnvelopeWizardResult.cs
@@ -1,3 +1,5 @@
+using EnvelopeGenerator.Domain.Constants;
+
 namespace EnvelopeGenerator.Server.Client.Components.Sender;
 
 public sealed record CreateEnvelopeWizardResult(
@@ -7,7 +9,7 @@ public sealed record CreateEnvelopeWizardResult(
     string Language,
     bool UseAccessCode,
     bool TFAEnabled,
-    int CertificationType,
+    CertificationType CertificationType,
     int FinalEmailToCreator,
     int FinalEmailToReceivers,
     bool SendReminderEmails,
diff --git a/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Pages/SenderEditorPage.razor b/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Pages/SenderEditorPage.razor
index 2384b531..24271fc4 100644
--- a/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Pages/SenderEditorPage.razor
+++ b/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Pages/SenderEditorPage.razor
@@ -652,7 +652,7 @@
     string _language = "de-DE";
     bool _useAccessCode;
     bool _tfaEnabled;
-    int _certificationType = (int)CertificationType.AdvancedElectronicSignature;
+    CertificationType _certificationType = CertificationType.AdvancedElectronicSignature;
     int _finalEmailToCreator = (int)FinalEmailType.No;
     int _finalEmailToReceivers = (int)FinalEmailType.No;
     bool _sendReminderEmails;
@@ -745,7 +745,7 @@
         _language = string.IsNullOrWhiteSpace(payload.Language) ? "de-DE" : payload.Language;
         _useAccessCode = payload.UseAccessCode;
         _tfaEnabled = payload.TFAEnabled;
-        _certificationType = NormalizeCertificationType(payload.CertificationType);
+        _certificationType = payload.CertificationType;
         _finalEmailToCreator = payload.FinalEmailToCreator;
         _finalEmailToReceivers = payload.FinalEmailToReceivers;
         _sendReminderEmails = payload.SendReminderEmails;
@@ -852,7 +852,7 @@
             if (_tfaEnabled)
                 _useAccessCode = true;
 
-            _certificationType = NormalizeCertificationType(envelope.CertificationType ?? (int)CertificationType.AdvancedElectronicSignature);
+            _certificationType = envelope.CertificationType ?? CertificationType.AdvancedElectronicSignature;
             _finalEmailToCreator = envelope.FinalEmailToCreator ?? (int)FinalEmailType.No;
             _finalEmailToReceivers = envelope.FinalEmailToReceivers ?? (int)FinalEmailType.No;
 
@@ -1046,7 +1046,7 @@
             _useAccessCode = true;
 
         if (envelopeType.CertificationType.HasValue)
-            _certificationType = NormalizeCertificationType(envelopeType.CertificationType.Value);
+            _certificationType = envelopeType.CertificationType.Value;
 
         if (envelopeType.FinalEmailToCreator.HasValue)
             _finalEmailToCreator = envelopeType.FinalEmailToCreator.Value;
@@ -1433,7 +1433,6 @@
     void NormalizeSettings()
     {
         _language = string.IsNullOrWhiteSpace(_language) ? "de-DE" : _language.Trim();
-        _certificationType = NormalizeCertificationType(_certificationType);
 
         if (_tfaEnabled)
             _useAccessCode = true;
@@ -1447,13 +1446,6 @@
             _expiresWarningWhenDays = _expiresWhenDays;
     }
 
-    static int NormalizeCertificationType(int value)
-    {
-        return value == 2
-            ? 2
-            : (int)CertificationType.AdvancedElectronicSignature;
-    }
-
     bool ValidateSettings(out string? message)
     {
         NormalizeSettings();
diff --git a/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Services/CreateEnvelopeBootstrapStorageService.cs b/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Services/CreateEnvelopeBootstrapStorageService.cs
index 2d13cc61..b4f92525 100644
--- a/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Services/CreateEnvelopeBootstrapStorageService.cs
+++ b/EnvelopeGenerator.Server/EnvelopeGenerator.Server.Client/Services/CreateEnvelopeBootstrapStorageService.cs
@@ -1,4 +1,5 @@
 using System.Text.Json;
+using EnvelopeGenerator.Domain.Constants;
 using Microsoft.JSInterop;
 
 namespace EnvelopeGenerator.Server.Client.Services;
@@ -49,7 +50,7 @@ public sealed record CreateEnvelopeBootstrapPayload(
     string Language,
     bool UseAccessCode,
     bool TFAEnabled,
-    int CertificationType,
+    CertificationType CertificationType,
     int FinalEmailToCreator,
     int FinalEmailToReceivers,
     bool SendReminderEmails,