using System;

using System.Diagnostics;

using System.Security.Cryptography;

using System.Text;

public class Program

{

    private const string _securityKey = "BA73F294584334BA";

    public static void Main()

    {

        var encryptedText = "9A7DA532324509A3";

        var decryptedText = DecryptCipherTextToPlainText(encryptedText);

        Console.WriteLine("DecryptedText = " + decryptedText);

        Console.ReadLine();

    }

    public static string DecryptCipherTextToPlainText(string textoCriptografado)

    {

            byte[] toEncryptArray = Convert.FromBase64String(textoCriptografado);

​

            MD5CryptoServiceProvider objMD5CryptoService = new MD5CryptoServiceProvider();

​

            //Gettting the bytes from the Security Key and Passing it to compute the Corresponding Hash Value.

            byte[] securityKeyArray = objMD5CryptoService.ComputeHash(UTF8Encoding.UTF8.GetBytes(_securityKey));

​

            //De-allocatinng the memory after doing the Job.

            objMD5CryptoService.Clear();

​

            var objTripleDESCryptoService = new TripleDESCryptoServiceProvider();

​

            //Assigning the Security key to the TripleDES Service Provider.

            objTripleDESCryptoService.Key = securityKeyArray;

​

            //Mode of the Crypto service is Electronic Code Book.

            objTripleDESCryptoService.Mode = CipherMode.ECB;

​

            //Padding Mode is PKCS7 if there is any extra byte is added.

            objTripleDESCryptoService.Padding = PaddingMode.None;

​

            byte[] DataToDecrypt = Convert.FromBase64String(textoCriptografado);

​

            var objCrytpoTransform = objTripleDESCryptoService.CreateDecryptor();

​

            //Transform the bytes array to resultArray

            byte[] resultArray = objCrytpoTransform.TransformFinalBlock(DataToDecrypt, 0, DataToDecrypt.Length);

​

            //Releasing the Memory Occupied by TripleDES Service Provider for Decryption.          

            objTripleDESCryptoService.Clear();

​

            //Convert and return the decrypted data/byte into string format.

            return UTF8Encoding.UTF8.GetString(resultArray);

     }

     public static string EncryptPlainTextToCipherText(string textoPlano)

     {

            //Getting the bytes of Input String.

            byte[] toEncryptedArray = UTF8Encoding.UTF8.GetBytes(textoPlano);

​

            MD5CryptoServiceProvider objMD5CryptoService = new MD5CryptoServiceProvider();

​

            //Gettting the bytes from the Security Key and Passing it to compute the Corresponding Hash Value.

            byte[] securityKeyArray = objMD5CryptoService.ComputeHash(UTF8Encoding.UTF8.GetBytes(_securityKey));

​

            //De-allocatinng the memory after doing the Job.

            objMD5CryptoService.Clear();

            var objTripleDESCryptoService = new TripleDESCryptoServiceProvider();

​

            //Assigning the Security key to the TripleDES Service Provider.

            objTripleDESCryptoService.Key = securityKeyArray;

​

            //Mode of the Crypto service is Electronic Code Book.

            objTripleDESCryptoService.Mode = CipherMode.ECB;

​

            //Padding Mode is PKCS7 if there is any extra byte is added.

            objTripleDESCryptoService.Padding = PaddingMode.None;

​

            var objCrytpoTransform = objTripleDESCryptoService.CreateEncryptor();

​

            //Transform the bytes array to resultArray

            byte[] resultArray = objCrytpoTransform.TransformFinalBlock(toEncryptedArray, 0, toEncryptedArray.Length);

​

            //Releasing the Memory Occupied by TripleDES Service Provider for Encryption.

            objTripleDESCryptoService.Clear();

​

            //Convert and return the encrypted data/byte into string format.

            return Convert.ToBase64String(resultArray, 0, resultArray.Length);

​

​

​

      }

​

}