DESEncryption.cs

// DES encryption

public string EncryptData(string strData, string strEncDcKey) {
  byte[] key = {}; //Encryption Key
  byte[] IV = {
    10,
    20,
    30,
    40,
    50,
    60,
    70,
    80
  };
  byte[] inputByteArray;
  try {
    key = Encoding.UTF8.GetBytes(strEncDcKey);
    // DESCryptoServiceProvider is a cryptography class defind in c#.
    DESCryptoServiceProvider ObjDES = new DESCryptoServiceProvider();
    inputByteArray = Encoding.UTF8.GetBytes(strData);
    MemoryStream Objmst = new MemoryStream();
    CryptoStream Objcs = new CryptoStream(Objmst, ObjDES.CreateEncryptor(key, IV), CryptoStreamMode.Write);
    Objcs.Write(inputByteArray, 0, inputByteArray.Length);
    Objcs.FlushFinalBlock();
    return Convert.ToBase64String(Objmst.ToArray()); //encrypted string
  }
  catch(System.Exception ex) {
    throw ex;
  }
}

// DES decryption
public string DecryptData(string strData, string strEndDcKey) {
  byte[] key = {}; // Key
  byte[] IV = {
    10,
    20,
    30,
    40,
    50,
    60,
    70,
    80
  };
  byte[] inputByteArray = new byte[strData.Length];
  try {
    key = Encoding.UTF8.GetBytes(strEndDcKey);
    DESCryptoServiceProvider ObjDES = new DESCryptoServiceProvider();
    inputByteArray = Convert.FromBase64String(strData);
    MemoryStream Objmst = new MemoryStream();
    CryptoStream Objcs = new CryptoStream(Objmst, ObjDES.CreateDecryptor(key, IV), CryptoStreamMode.Write);
    Objcs.Write(inputByteArray, 0, inputByteArray.Length);
    Objcs.FlushFinalBlock();
    Encoding encoding = Encoding.UTF8;
    return encoding.GetString(Objmst.ToArray());
  }
  catch(System.Exception ex) {
    throw ex;
  }
}