Improve whmcs-autoauth-invoice security

[tiagocaus]

How can I improve your code, causing each invoice sent to the client to generate a new hash.

It's possible?

[apeman76]

I think this would be possible, but it would require custom coding with custom PHP in your email template, this could be done via:
https://docs.whmcs.com/Email_Templates#Custom_PHP_Logic

[JonTheWong]

I'm looking into this. It might be possible to move the $timestamp into the creation of the user hash giving it a new hash per email, removing the 15 minutes expire and just make it unique per email. But will that unique hash expire?