Crypto.cs

  public class Crypto
        {

            public RijndaelManaged GetRijndaelManaged(String secretKey)
            {
                var keyBytes = new byte[16];
                var secretKeyBytes = Encoding.UTF8.GetBytes(secretKey);
                Array.Copy(secretKeyBytes, keyBytes, Math.Min(keyBytes.Length, secretKeyBytes.Length));
                return new RijndaelManaged
                {
                    Mode = CipherMode.CBC,
                    Padding = PaddingMode.PKCS7,
                    KeySize = 128,
                    BlockSize = 128,
                    Key = keyBytes,
                    IV = keyBytes
                };
            }

            public byte[] Encrypt(byte[] plainBytes, RijndaelManaged rijndaelManaged)
            {
                return rijndaelManaged.CreateEncryptor()
                    .TransformFinalBlock(plainBytes, 0, plainBytes.Length);
            }

            public byte[] Decrypt(byte[] encryptedData, RijndaelManaged rijndaelManaged)
            {
                return rijndaelManaged.CreateDecryptor()
                    .TransformFinalBlock(encryptedData, 0, encryptedData.Length);
            }

            /// <summary>
            /// Encrypts plaintext using AES 128bit key and a Chain Block Cipher and returns a base64 encoded string
            /// </summary>
            /// <param name="plainText">Plain text to encrypt</param>
            /// <param name="key">Secret key</param>
            /// <returns>Base64 encoded string</returns>
            public String Encrypt(String plainText, String key)
            {
                var plainBytes = Encoding.UTF8.GetBytes(plainText);
                return Convert.ToBase64String(Encrypt(plainBytes, GetRijndaelManaged(key)));
            }

            /// <summary>
            /// Decrypts a base64 encoded string using the given key (AES 128bit key and a Chain Block Cipher)
            /// </summary>
            /// <param name="encryptedText">Base64 Encoded String</param>
            /// <param name="key">Secret Key</param>
            /// <returns>Decrypted String</returns>
            public String Decrypt(String encryptedText, String key)
            {
                var encryptedBytes = Convert.FromBase64String(encryptedText);
                return Encoding.UTF8.GetString(Decrypt(encryptedBytes, GetRijndaelManaged(key)));
            }


        }