What are the potential pitfalls of using cookies for account protection in PHP?

Potential pitfalls of using cookies for account protection in PHP include the risk of cookie theft through cross-site scripting attacks or interception of unencrypted communication. To mitigate this risk, it is recommended to use secure cookies with the "HttpOnly" and "Secure" flags set, as well as encrypting sensitive data stored in cookies.

// Set a secure cookie with HttpOnly and Secure flags
setcookie("user_id", $user_id, time() + 3600, "/", "", true, true);