Using pseudorandom number generators (PRNGs) is security-sensitive. For example, it has led in the past to the following vulnerabilities:

When software generates predictable values in a context requiring unpredictability, it may be possible for an attacker to guess the next value that will be generated, and use this guess to impersonate another user or access sensitive information.

As the rand() and mt_rand functions rely on a pseudorandom number generator, it should not be used for security-critical applications or for protecting sensitive data.

Ask Yourself Whether

You are at risk if you answered yes to the first question and any of the following ones.

Recommended Secure Coding Practices

Questionable Code Example

$random = rand();
$random2 = mt_rand(0, 99);

Compliant Solution

$randomInt = random_int(0,99); // Compliant; generates a cryptographically secure random integer

See