Encriptar y desencriptar cadenas de texto con MD5. Visual Basic .NET

'Clase para encriptar y desencriptar cadenas de texto
'Fuente codigo: http://kellyschronicles.wordpress.com/2008/11/12/encryption-and-decryption-of-strings-with-vb-net/
'Fuente recomendada: http://jorgepedraza.wordpress.com/2011/01/29/funcion-cifrado-net/

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

'Ejemplo uso de la clase: Crypto.Encrypt(TextoOrigen,ClaveEncriptacion), Crypto.Decrypt(TextoEncriptado,ClaveEncriptacion)
Public Class Crypto
    Private Shared DES As New TripleDESCryptoServiceProvider
    Private Shared MD5 As New MD5CryptoServiceProvider
    Private Shared Function MD5Hash(ByVal value As String) As Byte()
        Return MD5.ComputeHash(ASCIIEncoding.ASCII.GetBytes(value))
    End Function

    Public Shared Function Encrypt(ByVal stringToEncrypt As String, ByVal key As String) As String
        DES.Key = Crypto.MD5Hash(key)
        DES.Mode = CipherMode.ECB
        Dim Buffer As Byte() = ASCIIEncoding.ASCII.GetBytes(stringToEncrypt)
        Return Convert.ToBase64String(DES.CreateEncryptor().TransformFinalBlock(Buffer, 0, Buffer.Length))
    End Function

    Public Shared Function Decrypt(ByVal encryptedString As String, ByVal key As String) As String
        Try
            DES.Key = Crypto.MD5Hash(key)
            DES.Mode = CipherMode.ECB
            Dim Buffer As Byte() = Convert.FromBase64String(encryptedString)
            Return ASCIIEncoding.ASCII.GetString(DES.CreateDecryptor().TransformFinalBlock(Buffer, 0, Buffer.Length))
        Catch ex As Exception
            MessageBox.Show("Invalid Key", "Decryption Failed", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
            Return ""
        End Try
    End Function
End Class