Use this instead. The key should be 8 characters in length

Private Sub btnTestEncryption_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnTestEncryption.Click

Dim s As String = "Encryption Test"

Dim p As String = "Password"

Dim r As String = EncryptDecrypt.Encrypt(s, p)

Debug.Print(r)

Dim t As String = EncryptDecrypt.Decrypt(r, p)

Debug.Print(t)

MsgBox("Done.")

End Sub