Is there a way to generate safely a unique ID after a form submission? (preferably server side)

So as per our requirement, once a form is submitted, a unique ID is generated, then sent via email to the submitter.

Now, one easy way would be to generate it client side in javascript, for example combining the current timestamp with the submitter's email address then hashing it into a complex ID, and passing it via hidden field in the form submission.

Passing then this unique either in the Contacts table or a CDO, then using a field merge to include it in the email.

That works, but the ID is generated client side. I was thinking if there was a way to generate or fetch a unique ID from server side (Eloqua) that you know of.