password_needs_rehash

(PHP 5 >= 5.5.0, PHP 7)

password_needs_rehash — Checks if the given hash matches the given options

Description

password_needs_rehash ( string $hash , int $algo [, array $options ] ) : bool

This function checks to see if the supplied hash implements the algorithm and options provided. If not, it is assumed that the hash needs to be rehashed.

Parameters

hash: A hash created by password_hash().
algo: A password algorithm constant denoting the algorithm to use when hashing the password.
options: An associative array containing options. See the password algorithm constants for documentation on the supported options for each algorithm.

Examples

Example #1 Usage of password_needs_rehash()


<?php

$password = 'rasmuslerdorf';
$hash = '$2y$10$YCFsG6elYca568hBi2pZ0.3LDL5wjgxct1N8w/oLR/jfHsiQwCqTS';

// The cost parameter can change over time as hardware improves
$options = array('cost' => 11);

// Verify stored hash against plain-text password
if (password_verify($password, $hash)) {
    // Check if a newer hashing algorithm is available
    // or the cost has changed
    if (password_needs_rehash($hash, PASSWORD_DEFAULT, $options)) {
        // If so, create a new hash, and replace the old one
        $newHash = password_hash($password, PASSWORD_DEFAULT, $options);
    }

    // Log user in
}
?>

Return Values

Returns TRUE if the hash should be rehashed to match the given algo and options, or FALSE otherwise.