Uso de DES en .net

Esta funcion funciona (suponiendo que el largo del texto es siempre multiplo
de 8):

Function EncryptString_DES_CBC( _
ByVal text As String, _
ByVal key() As Byte, _
ByVal iv() As Byte) As String

Dim des As New DESCryptoServiceProvider
Dim data() As Byte = System.Text.Encoding.ASCII.GetBytes(text)

des.Mode = CipherMode.CBC
des.Key = key
des.IV = iv

Dim transform As ICryptoTransform = des.CreateEncryptor()

Dim enc(data.Length - 1) As Byte
For i As Integer = 0 To data.Length - 1 Step 8
transform.TransformBlock(data, i, 8, enc, i)
Next

Return ToHex(enc)

End Function

Function ToHex(ByVal data() As Byte) As String
Dim hex As New System.Text.StringBuilder

For Each b As Byte In data
hex.AppendFormat("{0:X2}", b)
Next

Return hex.ToString

End Function

MessageBox.Show(EncryptString_DES_CBC("Now is the time for all ", _
New Byte() {&H1, &H23, &H45, &H67, &H89, &HAB, &HCD, &HEF}, _
New Byte() {&H12, &H34, &H56, &H78, &H90, &HAB, &HCD, &HEF}))

Eduardo A. Morcillo [MS MVP VB]
http://www.mvps.org/emorcillo