Happy flow for creating realms works

But needs more validating...

IdentityShroud.Core.Tests/Services/EncryptionServiceTests.cs

@@ -0,0 +1,22 @@
+using System.Security.Cryptography;
+using IdentityShroud.Core.Services;
+
+namespace IdentityShroud.Core.Tests.Services;
+
+public class EncryptionServiceTests
+{
+    [Fact]
+    public void RoundtripWorks()
+    {
+        // setup
+        string key = Convert.ToBase64String(RandomNumberGenerator.GetBytes(32));
+        EncryptionService sut = new(key);
+        byte[] input = RandomNumberGenerator.GetBytes(16);
+        
+        // act
+        var cipher = sut.Encrypt(input);
+        var result = sut.Decrypt(cipher);
+
+        Assert.Equal(input, result);
+    }
+}