Final answer:
The security architect is attempting to prevent XSS (Cross-Site Scripting) attack.
Step-by-step explanation:
The security architect is attempting to prevent XSS (Cross-Site Scripting) attack by suggesting the addition of the HTML element and server-side function to generate a random number. XSS attacks involve injecting malicious scripts into a website, which can be used to steal sensitive information or hijack user sessions. By generating a random number on the page, the architect is adding an extra layer of protection to prevent this kind of attack.