5-improve-encrypted-storage (#6)

Added the use of DEK's for encryption of secrets. Both the KEK's and DEK's are stored in a way that you can have multiple key of which one is active. But the others are still available for decrypting. This allows for implementing key rotation.

Co-authored-by: eelke <eelke@eelkeklein.nl>
Co-authored-by: Eelke76 <31384324+Eelke76@users.noreply.github.com>
Reviewed-on: #6

IdentityShroud.Core/Security/Keys/KeyProviderFactory.cs

@@ -0,0 +1,17 @@
+using IdentityShroud.Core.Security.Keys.Rsa;
+
+namespace IdentityShroud.Core.Security.Keys;
+
+public class KeyProviderFactory : IKeyProviderFactory
+{
+    public IKeyProvider CreateProvider(string keyType)
+    {
+        switch (keyType)
+        {
+            case "RSA":
+                return new RsaProvider();
+            default:
+                throw new NotImplementedException();
+        }
+    }
+}