VB .NET - Encriptar/Descriptar texto utilizando o algoritmo TripleDES

Imports System.Text

Imports System.Security.Cryptography

Public Class Form1

    Private Const Chave As String = "TesteDeChave"

    Private TripleDES As New TripleDESCryptoServiceProvider

    Private MD5 As New MD5CryptoServiceProvider

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Try

            Dim byteArray() As Byte = ASCIIEncoding.ASCII.GetBytes(Chave)

            TripleDES.Key = MD5.ComputeHash(byteArray)

            TripleDES.Mode = CipherMode.ECB

            Dim Buffer As Byte() = ASCIIEncoding.ASCII.GetBytes(TextBox1.Text)

            TextBox2.Text = Convert.ToBase64String(TripleDES.CreateEncryptor().TransformFinalBlock(Buffer, 0, Buffer.Length))

        Catch ex As Exception

            MessageBox.Show(ex.Message)

        End Try

    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

        Try

            Dim byteArray() As Byte = ASCIIEncoding.ASCII.GetBytes(Chave)

            TripleDES.Key = MD5.ComputeHash(byteArray)

            TripleDES.Mode = CipherMode.ECB

            Dim Buffer As Byte() = Convert.FromBase64String(TextBox2.Text)

            Label3.Text = "Texto Descriptografado: " & ASCIIEncoding.ASCII.GetString(TripleDES.CreateDecryptor().TransformFinalBlock(Buffer, 0, Buffer.Length))

        Catch ex As Exception

            MessageBox.Show(ex.Message)

        End Try

    End Sub

End Class

 Espero ter ajudado... Até mais, abraços!

Projeto neste link: http://www.mediafire.com/?g07mikvi4gfw0pd