using System;

using System.Text;

using System.IO;

using System.Security.Cryptography;

​

public class Program

{

    public static void Main()

    {

            var encryptedText = Encrypt("Test string", "test");

            Console.WriteLine("Encrypted Text: " + encryptedText);

            var decryptedText = Decrypt(encryptedText, "test");

            Console.WriteLine("Decrypted Text: " + decryptedText);

    }

    public static string Encrypt(string  plainText, string  passPhrase)

    {

        byte[] initVectorBytes = Encoding.ASCII.GetBytes("pemgail9uzpgzl88");

        byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);

​

        PasswordDeriveBytes password = new PasswordDeriveBytes

        (

            passPhrase,

            null

        );

        byte[] keyBytes = password.GetBytes(256 / 8);

        RijndaelManaged symmetricKey = new RijndaelManaged();

        symmetricKey.Mode = CipherMode.CBC;

        symmetricKey.Padding = PaddingMode.PKCS7;

        ICryptoTransform encryptor = symmetricKey.CreateEncryptor

        (

            keyBytes,

            initVectorBytes

        );

        MemoryStream memoryStream = new MemoryStream();

        CryptoStream cryptoStream = new CryptoStream

        (

            memoryStream,

            encryptor,

            CryptoStreamMode.Write

        );

        cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);

        cryptoStream.FlushFinalBlock();

        byte[] cipherTextBytes = memoryStream.ToArray();

        memoryStream.Close();

        cryptoStream.Close();

        string cipherText = Convert.ToBase64String(cipherTextBytes);

        return cipherText;

    }

​

     public static string Decrypt(string  cipherText, string  passPhrase)

    {

        byte[] initVectorBytes = Encoding.ASCII.GetBytes("pemgail9uzpgzl88");

        byte[] cipherTextBytes = Convert.FromBase64String(cipherText);

​

        PasswordDeriveBytes password = new PasswordDeriveBytes

        (

            passPhrase,

            null

        );

​

        byte[] keyBytes = password.GetBytes(256 / 8);

        RijndaelManaged symmetricKey = new RijndaelManaged();

        symmetricKey.Mode = CipherMode.CBC;

        symmetricKey.Padding = PaddingMode.PKCS7;

        ICryptoTransform decryptor = symmetricKey.CreateDecryptor

        (

            keyBytes,

            initVectorBytes

        );

​

        MemoryStream memoryStream = new MemoryStream(cipherTextBytes);

        CryptoStream cryptoStream = new CryptoStream

        (

            memoryStream,

            decryptor,

            CryptoStreamMode.Read

        );

​

        byte[] plainTextBytes = new byte[cipherTextBytes.Length];

​

        int decryptedByteCount = cryptoStream.Read

        (

            plainTextBytes,

            0,

            plainTextBytes.Length

        );

​

        memoryStream.Close();

        cryptoStream.Close();

        string plainText = Encoding.UTF8.GetString

        (

            plainTextBytes,

            0,

            decryptedByteCount

        );

​

        return plainText;

    }

}