Sagepay Script

Hello, I need a custom little sagepay script to tag onto my website. It simply needs to run from a submit button. Its sagepay form that we are using. I have started the code below but sagepay require to encrypt the data and not sure how to so this, you may already have a script or if you have done this before thats great. See code below:


<form action="


<input type="hidden" name="Vendor" value="
<input type="hidden" name="Crypt" value="



function submitform()
{
document.SagePayForm.submit();
}
submitform();