Encryption/Decryption with Base64

Copied from http://addressof.com/blog/archive/2004/10/19/997.aspx


Private Function TripleDESEncode(ByVal value As String, ByVal key As String) As String
Dim des As New Security.Cryptography.TripleDESCryptoServiceProvider
des.IV = New Byte(7) {}
Dim pdb As New Security.Cryptography.PasswordDeriveBytes(key, New Byte(-1) {})
des.Key = pdb.CryptDeriveKey("RC2", "MD5", 128, New Byte(7) {})
Dim ms As New IO.MemoryStream((value.Length * 2) - 1)
Dim encStream As New Security.Cryptography.CryptoStream(ms, des.CreateEncryptor(), Security.Cryptography.CryptoStreamMode.Write)
Dim plainBytes As Byte() = Text.Encoding.UTF8.GetBytes(value)
encStream.Write(plainBytes, 0, plainBytes.Length)
encStream.FlushFinalBlock()
Dim encryptedBytes(CInt(ms.Length - 1)) As Byte
ms.Position = 0
ms.Read(encryptedBytes, 0, CInt(ms.Length))
encStream.Close()
Return Convert.ToBase64String(encryptedBytes)
End Function



Public Function TripleDESDecode(ByVal value As String, ByVal key As String) As String
Dim des As New Security.Cryptography.TripleDESCryptoServiceProvider
des.IV = New Byte(7) {}
Dim pdb As New Security.Cryptography.PasswordDeriveBytes(key, New Byte(-1) {})
des.Key = pdb.CryptDeriveKey("RC2", "MD5", 128, New Byte(7) {})
Dim encryptedBytes As Byte() = Convert.FromBase64String(value)
Dim ms As New IO.MemoryStream(value.Length)
Dim decStream As New Security.Cryptography.CryptoStream(ms, des.CreateDecryptor(), Security.Cryptography.CryptoStreamMode.Write)
decStream.Write(encryptedBytes, 0, encryptedBytes.Length)
decStream.FlushFinalBlock()
Dim plainBytes(CInt(ms.Length - 1)) As Byte
ms.Position = 0
ms.Read(plainBytes, 0, CInt(ms.Length))
decStream.Close()
Return Text.Encoding.UTF8.GetString(plainBytes)
End Function


TEST This from:
Sub Main()
Dim key As String = "a1B@c3D$"
Dim original As String = "This is a test, blah, blah, blah."
Console.WriteLine("Original" & vbCrLf & "-----------------")
Console.WriteLine(original & vbCrLf)
Dim encrypted As String = TripleDESEncode(original, key)
Console.WriteLine("Encrypted" & vbCrLf & "-----------------")
Console.WriteLine(encrypted & vbCrLf)
Dim decrypted As String = TripleDESDecode(encrypted, key)
Console.WriteLine("Decrypted" & vbCrLf & "-----------------")
Console.WriteLine(decrypted & vbCrLf)
Console.ReadLine()
End Sub