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/Services/RealmContext.cs

@@ -0,0 +1,26 @@
+using IdentityShroud.Core.Contracts;
+using IdentityShroud.Core.Model;
+using Microsoft.AspNetCore.Http;
+
+namespace IdentityShroud.Core.Services;
+
+public class RealmContext(
+    IHttpContextAccessor accessor,
+    IRealmService realmService) : IRealmContext
+{
+    public Realm GetRealm()
+    {
+        return (Realm)accessor.HttpContext.Items["RealmEntity"];
+    }
+
+    public async Task<IList<RealmDek>> GetDeks(CancellationToken ct = default)
+    {
+        Realm realm = GetRealm();
+        if (realm.Deks.Count == 0)
+        {
+            await realmService.LoadDeks(realm);
+        }
+
+        return realm.Deks;
+    }
+}