What are the potential risks associated with relying solely on registration date and user ID for generating activation links in PHP applications?

Relying solely on registration date and user ID for generating activation links in PHP applications can pose security risks as these values can potentially be guessed or manipulated by malicious users. To mitigate this risk, it is advisable to incorporate additional random tokens or unique identifiers in the activation link generation process.

// Generate a random token to include in the activation link
$token = bin2hex(random_bytes(16));

// Construct the activation link with the random token
$activation_link = "https://example.com/activate.php?token=$token&user_id=$user_id";

// Store the token in the database for verification during activation process
// Remember to sanitize and validate user input before storing it in the database