What are the potential pitfalls of using uniqid() for generating activation codes in PHP?

Using uniqid() for generating activation codes in PHP can potentially lead to activation codes that are not truly unique, especially in high traffic scenarios where multiple requests are made at the same time. To ensure uniqueness, it is recommended to combine uniqid() with other unique identifiers such as microtime() or random_bytes().

// Generate a unique activation code using uniqid() combined with microtime()
$activationCode = uniqid() . microtime(true);

// Alternatively, you can combine uniqid() with random_bytes() for added uniqueness
$activationCode = uniqid() . bin2hex(random_bytes(4));