Example of (Secure Hash Algorithm)SHA in c#.net

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using System.Security.Cryptography;

namespace WindowsFormsApplication3

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            HASobj = new HAS("abc");

            string s = obj.EncryptData("jay jagannath");

            MessageBox.Show(s);

            string t = obj.DecryptData(s);

            MessageBox.Show(t);

        }

    }

    class HAS

    {

        TripleDESCryptoServiceProvider tripleDes = new TripleDESCryptoServiceProvider();

        public PISOFTEKHAS(string key)

        {

            tripleDes.Key = TruncateHash(key, tripleDes.KeySize / 8);

            tripleDes.IV = TruncateHash("", tripleDes.BlockSize / 8);

        }

        private byte[] TruncateHash(string key, int length)

        {

            SHA1CryptoServiceProvider sha1 = new SHA1CryptoServiceProvider();

            byte[] keyBytes = System.Text.Encoding.Unicode.GetBytes(key);

            byte[] hash = sha1.ComputeHash(keyBytes);

            Array.Resize(ref hash, length);

            return hash;

        }

        public string EncryptData(string plaintext)

        {

            byte[] plaintextBytes = System.Text.Encoding.Unicode.GetBytes(plaintext);

            System.IO.MemoryStream ms = new System.IO.MemoryStream();

            CryptoStream encStream = new CryptoStream(ms, tripleDes.CreateEncryptor(), System.Security.Cryptography.CryptoStreamMode.Write);

            encStream.Write(plaintextBytes, 0, plaintextBytes.Length);

            encStream.FlushFinalBlock();

            return Convert.ToBase64String(ms.ToArray());

        }

        public string DecryptData(string encryptedtext)

        {

            byte[] encryptedBytes = Convert.FromBase64String(encryptedtext);

            System.IO.MemoryStream ms = new System.IO.MemoryStream();

            CryptoStream decStream = new CryptoStream(ms, tripleDes.CreateDecryptor(), System.Security.Cryptography.CryptoStreamMode.Write);

            decStream.Write(encryptedBytes, 0, encryptedBytes.Length);

            decStream.FlushFinalBlock();

            return System.Text.Encoding.Unicode.GetString(ms.ToArray());

        }

    }

}