public class TripleDES

      {

            #region Private Members

            // privateKey and initVector default for TripleDES

            private byte []privateKey = {};

            private byte []initVector = {};

            // These members will be used to perform encryption and decryption.

            private ICryptoTransform encryptor      = null;

            private ICryptoTransform decryptor      = null;

            #endregion

            public TripleDES()

            {

                  // Create a Provider for TripleDES Encryption.

                  TripleDESCryptoServiceProvider tdesProvider =

                                          new TripleDESCryptoServiceProvider();

                  // Initialize the encryptor we are going to use.

                  encryptor = tdesProvider.CreateEncryptor(

                                          privateKey,

                                          initVector);

                  // Initialize the decryptor we are going to use.

                  decryptor = tdesProvider.CreateDecryptor(

                                          privateKey,

                                          initVector);            }

            #region Encryption Functions

            /// <summary>

            /// Encrypts a string value generating a base64-encoded string.

            /// </summary>

            /// <param name="plainText">

/// Plain Text string to be encrypted.

/// </param>

            /// <returns>

/// Cipher text formated as a base64-encoded string.

/// </returns>

            public string Encrypt(string plainText)

            {

                  return Encrypt(Encoding.UTF8.GetBytes(plainText));

            }

            /// <summary>

            /// Encrypts a byte array generating a base64-encoded string.

            /// </summary>

            /// <param name="plainTextBytes">

/// Plain text bytes to be encrypted.

/// </param>

            /// <returns>Cipher text formated as a base64-encoded string.

/// </returns>

            public string Encrypt(byte[] plainTextBytes)

            {

                  return Convert.ToBase64String(

EncryptToBytes(plainTextBytes));

            }

            /// <summary>

            /// Encrypts a string value generating a byte array of cipher text.

            /// </summary>

            /// <param name="plainText">Plain text string to be encrypted.

/// </param>

            /// <returns>Cipher text formatted as a byte array.</returns>

            public byte[] EncryptToBytes(string plainText)

            {

                  return EncryptToBytes(Encoding.UTF8.GetBytes(plainText));

            }

            /// <summary>

            /// Encrypts a byte array generating a byte array of cipher text.

            /// </summary>

            /// <param name="plainTextBytes">Plain text bytes to be encrypted.

/// </param>

            /// <returns>Cipher text formatted as a byte array.</returns>

            public byte[] EncryptToBytes(byte[] plainTextBytes)

            {

                  // Encryption will be performed using memory stream.

                  MemoryStream encryptedStream = new MemoryStream();

                  lock (this)

                  {

                        // Init encrypting stream.

                        CryptoStream cryptStream = new CryptoStream(

                                                      encryptedStream,

                                                      encryptor,

                                                      CryptoStreamMode.Write);

                        // Start encrypting data.

                        cryptStream.Write(

plainTextBytes,

0,

plainTextBytes.Length);

                        // Finish the encryption operation.

                        cryptStream.FlushFinalBlock();

                        // Move encrypted data from memory to array.

                        byte[] result = encryptedStream.ToArray();

                        // Close memory streams.

                        encryptedStream.Close();

                        cryptStream.Close();

                        // Return encrypted data.

                        return result;

                  }

            }

            #endregion

            #region Decryption routines

            /// <summary>

            /// Decrypts a base64-encoded cipher text value

/// generating a string result.

            /// </summary>

            /// <param name="cipherText">

            /// Base64-encoded cipher text string to be decrypted.

            /// </param>

            /// <returns>

            /// Decrypted string value.

            /// </returns>

            public string Decrypt(string cipherText)

            {

                  return Decrypt(Convert.FromBase64String(cipherText));

            }

            /// <summary>

            /// Decrypts a byte array containing cipher text value and

/// generates a string result.

            /// </summary>

            /// <param name="cipherTextBytes">

            /// Byte array containing encrypted data.

            /// </param>

            /// <returns>

            /// Decrypted string value.

            /// </returns>

            public string Decrypt(byte[] cipherTextBytes)

            {

                  return Encoding.UTF8.GetString(

DecryptToBytes(cipherTextBytes));

            }

            /// <summary>

            /// Decrypts a base64-encoded cipher text value and generates

/// a byte array of plain text data.

            /// </summary>

            /// <param name="cipherText">

            /// Base64-encoded cipher text string to be decrypted.

            /// </param>

            /// <returns>

            /// Byte array containing decrypted value.

            /// </returns>

            public byte[] DecryptToBytes(string cipherText)

            {

                  return DecryptToBytes(Convert.FromBase64String(cipherText));

            }

            /// <summary>

            /// Decrypts a base64-encoded cipher text value and generates

/// a byte array of plain text data.

            /// </summary>

            /// <param name="cipherTextBytes">

            /// Byte array containing encrypted data.

            /// </param>

            /// <returns>

            /// Byte array containing decrypted value.

            /// </returns>

            public byte[] DecryptToBytes(byte[] cipherTextBytes)

            {

                  byte[]      decryptedBytes          = null;

                  byte[]      plainTextBytes          = null;

                  int         decryptedByteCount      = 0;

                  MemoryStream memoryStream = new MemoryStream(cipherTextBytes);

                  // Since we do not know how big decrypted value will be, use

// the same size as cipher text. Cipher text is always longer

// than plain text (in block cipher encryption), so we will

// just use the number of decrypted data byte after we know

// how big it is.

                  decryptedBytes = new byte[cipherTextBytes.Length];

                  // Thread Safe

                  lock (this)

                  {

                        // Initialize decryption stream

                        CryptoStream cryptoStream = new CryptoStream(

                                                memoryStream,

                                                decryptor,

                                                CryptoStreamMode.Read);

                        // Decrypting data and get the count of plain text.

                        decryptedByteCount = cryptoStream.Read(

decryptedBytes,

                                                0,

                                                decryptedBytes.Length);

                        // Release Memory.

                        cryptoStream.Close();

                        memoryStream.Close();

                  }

                  // Allocate the byte array to hold the original plain text.

                  plainTextBytes = new byte[decryptedByteCount];

                  // Copy original plain text value.

                  Array.Copy(decryptedBytes, 0, plainTextBytes,

                                    0, decryptedByteCount);

                  // Return original plain text value.

                  return plainTextBytes;

            }

            #endregion

      }