static byte[] Decrypt(byte[] encryptedString) { using (var provider = new AesCryptoServiceProvider()) { provider.Key = EncriptationKey; using (var ms = new MemoryStream(encryptedString)) { // Read the first 16 bytes which is the IV. byte[] iv = new byte[16]; ms.Read(iv, 0, 16); provider.IV = iv; using (var decryptor = provider.CreateDecryptor()) { using (var cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Read)) { return cs.ReadAllBytes(); } } } } }