Imports System.IO
Imports System.Security.Cryptography
Imports System.Text


Public Class Form1
public static string TripleDESDecode(string value, string key)
{
    TripleDESCryptoServiceProvider provider = new TripleDESCryptoServiceProvider();
    provider.IV = new byte[8];
    provider.Key = new PasswordDeriveBytes(key, new byte[0]).CryptDeriveKey("RC2", "MD5", 0x80, new byte[8]);
    byte[] buffer = Convert.FromBase64String(value);
    MemoryStream stream2 = new MemoryStream(value.Length);
    CryptoStream stream = new CryptoStream(stream2, provider.CreateDecryptor(), CryptoStreamMode.Write);
    stream.Write(buffer, 0, buffer.Length);
    stream.FlushFinalBlock();
    byte[] buffer2 = new byte[((int) (stream2.Length - 1L)) + 1];
    stream2.Position = 0L;
    stream2.Read(buffer2, 0, (int) stream2.Length);
    stream.Close();
    return Encoding.UTF8.GetString(buffer2);
}

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        TextBox3.Text = TripleDESDecode(TextBox1.Text, TextBox2.Text)
    End Sub
End Class