PHP Manual
Hash-Funktionen
Generate a PBKDF2 key derivation of a supplied password

hash_pbkdf2

(PHP 5 >= 5.5.0, PHP 7, PHP 8)

hash_pbkdf2 — Generate a PBKDF2 key derivation of a supplied password

Beschreibung

hash_pbkdf2(
    string $algo,
    string $password,
    string $salt,
    int $iterations,
    int $length = 0,
    bool $binary = false
): string

Parameter-Liste

algo

Name of selected hashing algorithm (i.e. md5, sha256, haval160,4, etc..) See hash_algos() for a list of supported algorithms.

password

The password to use for the derivation.

salt

The salt to use for the derivation. This value should be generated randomly.

iterations

The number of internal iterations to perform for the derivation.

length

The length of the output string. If binary is true this corresponds to the byte-length of the derived key, if binary is false this corresponds to twice the byte-length of the derived key (as every byte of the key is returned as two hexits).

If 0 is passed, the entire output of the supplied algorithm is used.

binary

When set to true, outputs raw binary data. false outputs lowercase hexits.

Rückgabewerte

Returns a string containing the derived key as lowercase hexits unless binary is set to true in which case the raw binary representation of the derived key is returned.

Fehler/Exceptions

An E_WARNING will be raised if the algorithm is unknown, the iterations parameter is less than or equal to 0, the length is less than 0 or the salt is too long (greater than INT_MAX - 4).

Changelog

Version	Beschreibung
7.2.0	Usage of non-cryptographic hash functions (adler32, crc32, crc32b, fnv132, fnv1a32, fnv164, fnv1a64, joaat) was disabled.

Beispiele

Beispiel #1 hash_pbkdf2() example, basic usage


<?php
$password = "password";
$iterations = 1000;

// Generate a random IV using openssl_random_pseudo_bytes()
// random_bytes() or another suitable source of randomness
$salt = openssl_random_pseudo_bytes(16);

$hash = hash_pbkdf2("sha256", $password, $salt, $iterations, 20);
var_dump($hash);

// for raw binary, the $length needs to be halved for equivalent results
$hash = hash_pbkdf2("sha256", $password, $salt, $iterations, 10, true);
var_dump(bin2hex($hash));?>

Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:

string(20) "120fb6cffcf8b32c43e7"
string(20) "120fb6cffcf8b32c43e7"

Anmerkungen

Achtung

The PBKDF2 method can be used for hashing passwords for storage. However, it should be noted that password_hash() or crypt() with CRYPT_BLOWFISH are better suited for password storage.

Siehe auch

crypt() - Einweg-String-Hashing
password_hash() - Erstellt einen Passwort-Hash
hash() - Berechnet den Hash einer Nachricht
hash_algos() - Liefert eine Liste der verfügbaren Hashing-Algorithmen
hash_init() - Initialisiert einen schrittweisen Hashing-Kontext
hash_hmac() - Berechnet einen Hash mit Schlüssel unter Verwendung von HMAC
hash_hmac_file() - Berechnet einen Hash einer Datei mit Schlüssel unter Verwendung von HMAC
openssl_pbkdf2() - Generates a PKCS5 v2 PBKDF2 string