bunch of fixes

Toolkit.Foundation/AesDecryptor.cs

@@ -0,0 +1,28 @@
+using System.Security.Cryptography;
+
+namespace Toolkit.Foundation;
+
+public class AesDecryptor :
+    IDecryptor
+{
+    private const int IvSize = 16;
+
+    public byte[] Decrypt(byte[] cipher, byte[] key)
+    {
+        Span<byte> iv = cipher.AsSpan(0, IvSize);
+        ReadOnlySpan<byte> encryptedContent = cipher.AsSpan(IvSize);
+
+        using Aes aes = Aes.Create();
+        aes.Key = key;
+        aes.IV = iv.ToArray();
+
+        using MemoryStream memoryStream = new(encryptedContent.ToArray());
+        using ICryptoTransform decryptor = aes.CreateDecryptor(aes.Key, aes.IV);
+        using CryptoStream cryptoStream = new(memoryStream, decryptor, CryptoStreamMode.Read);
+
+        using MemoryStream resultStream = new();
+        cryptoStream.CopyTo(resultStream);
+
+        return resultStream.ToArray();
+    }
+}