Question

is there anyway that I can convert this to use RSA encryption? im kinda new to VB.Net and even worse at encryption. thanks

Imports System.Text
Imports System.Security.Cryptography
Imports System.IO
Public Class ClsEncryption
Public Shared Function DESEncrypt(ByVal Data As String, ByVal Key As String) As String
    Dim DES As New System.Security.Cryptography.DESCryptoServiceProvider
    Dim dHash As New System.Security.Cryptography.MD5CryptoServiceProvider
    Dim encrypted As String = ""
    Try
        Dim hash(7) As Byte
        Dim temp As Byte() = dHash.ComputeHash(System.Text.ASCIIEncoding.ASCII.GetBytes(Key))
        Array.Copy(temp, 0, hash, 0, 8)
        DES.Key = hash
        DES.Mode = Security.Cryptography.CipherMode.ECB
        Dim DESEncrypter As System.Security.Cryptography.ICryptoTransform = DES.CreateEncryptor
        Dim Buffer As Byte() = System.Text.ASCIIEncoding.ASCII.GetBytes(Data)
        encrypted = Convert.ToBase64String(DESEncrypter.TransformFinalBlock(Buffer, 0, Buffer.Length))
        Return encrypted
    Catch ex As Exception
    End Try
End Function
End Class

Answer 1

For encryption you could pass the (trusted) public key instead of the DES key to the function. You could keep the encryption the same as the it is now, but instead of using the now replaced DES key, you should generate this key using a random number generator. Then you can encrypt the DES key using PKCS#1 v1.5 padding. Finally, you require some kind of container format to send the encrypted DES key and the ciphertext.

To decrypt, use the private key of the asymmetric key pair to decrypt the DES key, and then perform the decryption of the plain text as it is now.

Note that you should use an IV, should not use DES or ECB mode encryption, ASCII is better replaced by UTF-8 etc. etc. If this is for a project of any importance, ask for expert help. If possible, find out a library function to do all this for you, e.g. something that creates PKCS#7/CMS EncryptedData structures.