using System;

using System.IO;

using System.Security.Cryptography;

using System.Text;

public class Program

{

    static string _content = "test content 1 2 3";

static TripleDESCryptoServiceProvider _tdes = new TripleDESCryptoServiceProvider();

​

public static void Main()

{

    _tdes.GenerateKey();

    _tdes.GenerateIV();

​

    string encrypted = encrypt(_content);

    Console.WriteLine(encrypted);

​

    string decrypted = decrypt(encrypted);

    Console.WriteLine(decrypted);

}

​

// Encrypts the data

public static string encrypt(string unencrypted)

{

    try

    {

        // Create or open the specified file.

        MemoryStream ms = new MemoryStream();

​

        // Create a CryptoStream using the FileStream 

        // and the passed key and initialization vector (IV).

        CryptoStream cStream = new CryptoStream(ms,

            _tdes.CreateEncryptor(_tdes.Key, _tdes.IV),

            CryptoStreamMode.Write);

​

        // Create a StreamWriter using the CryptoStream.

        StreamWriter sWriter = new StreamWriter(cStream);

​

        // Write the data to the stream 

        // to encrypt it.

        sWriter.WriteLine(unencrypted);

        sWriter.Flush();

        cStream.FlushFinalBlock();

​

        ms.Position = 0;

        string encrypted = Convert.ToBase64String(ms.ToArray());

​

        // Close the streams and

        // close the file.

        sWriter.Close();

        cStream.Close();

        ms.Close();

​

        return encrypted;

    }

    catch (CryptographicException e)

    {

        Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);

        //return false;

    }

    catch (UnauthorizedAccessException e)

    {

        Console.WriteLine("A file access error occurred: {0}", e.Message);

        //return false;

    }

​

    return null;

}

​

// Decrypts the file

public static string decrypt(string encrypted)

{

    try

    {

        // Create or open the specified file. 

        MemoryStream encryptedStream = new MemoryStream(Convert.FromBase64String(encrypted));

​

        // Create a CryptoStream using the FileStream 

        // and the passed key and initialization vector (IV).

        CryptoStream cStream = new CryptoStream(encryptedStream,

            _tdes.CreateDecryptor(_tdes.Key, _tdes.IV),

            CryptoStreamMode.Read); // Exception happens here

​

        // Create a StreamReader using the CryptoStream.

        StreamReader sReader = new StreamReader(cStream);

​

        // Read the data from the stream 

        // to decrypt it.

        String val = sReader.ReadToEnd();

​

        // Close the streams and

        // close the file.

        sReader.Close();

        cStream.Close();

        encryptedStream.Close();

​

        return val;

    }

    catch (CryptographicException e)

    {

        Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);

        //return false;

    }

    catch (UnauthorizedAccessException e)

    {

        Console.WriteLine("A file access error occurred: {0}", e.Message);

        //return false;

    }

​

    return null;

}

​

}