diff --git a/FitConnect/FunctionalBaseClass.cs b/FitConnect/FunctionalBaseClass.cs
index eeb68911e71e1eb79dae8610e2dd3124790eca7f..2de705683aaac8205894770455cf2f916e475beb 100644
--- a/FitConnect/FunctionalBaseClass.cs
+++ b/FitConnect/FunctionalBaseClass.cs
@@ -6,7 +6,7 @@ using Microsoft.Extensions.Logging;
 
 namespace FitConnect;
 
-public abstract class FunctionalBaseClass : EncryptionBaseClass {
+public class FunctionalBaseClass : EncryptionBaseClass {
     protected readonly ILogger? logger;
     public FitConnectEndpoints Endpoints { get; }
 
diff --git a/SenderTest/SenderEncryptionTest.cs b/SenderTest/SenderEncryptionTest.cs
index d94351620d382d38cd1bfa7885b91dd3f752aa57..768b0f0937793c06d3fe9d43e5176f27ecc767d0 100644
--- a/SenderTest/SenderEncryptionTest.cs
+++ b/SenderTest/SenderEncryptionTest.cs
@@ -1,6 +1,8 @@
 using System;
 using System.Buffers.Text;
+using System.IO;
 using System.Security.Cryptography;
+using System.Security.Cryptography.X509Certificates;
 using System.Text;
 using FitConnect;
 using FluentAssertions;
@@ -21,6 +23,23 @@ public class SenderEncryptionTest {
             FitConnectEndpoints.Create(FitConnectEndpoints.EndpointType.Development));
     }
 
+    private X509Certificate2 CreateSelfSignedCertificate() {
+        var req = new CertificateRequest("cn=foobar", ECDsa.Create(), HashAlgorithmName.SHA256);
+        var cert = req.CreateSelfSigned(DateTimeOffset.Now, DateTimeOffset.Now.AddYears(5));
+
+        // Create PFX (PKCS #12) with private key
+        File.WriteAllBytes("../../../mycert.pfx", cert.Export(X509ContentType.Pfx, "P@55w0rd"));
+
+        // Create Base 64 encoded CER (public key only)
+        File.WriteAllText("../../../mycert.cer",
+            "-----BEGIN CERTIFICATE-----\r\n"
+            + Convert.ToBase64String(cert.Export(X509ContentType.Cert),
+                Base64FormattingOptions.InsertLineBreaks)
+            + "\r\n-----END CERTIFICATE-----");
+
+        return cert;
+    }
+
     [Test]
     public void CryptWithPublicKeyImport() {
         var publicKey = Convert.FromBase64String(