password_needs_rehash
(PHP 5 >= 5.5.0, PHP 7, PHP 8)
password_needs_rehash — Checks if the given hash matches the given options
Description
password_needs_rehash(string
$hash, string|int|null $algo, array $options = []): boolThis 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.
Return Values
Returns true if the hash should be rehashed to match the given
algo and options, or false
otherwise.
Changelog
| Version | Description |
|---|---|
| 7.4.0 |
The algo parameter expects a string now, but still accepts
ints for backward compatibility.
|
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
}
?>
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