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openssl_pbkdf2

(PHP 5 >= 5.5.0, PHP 7)

openssl_pbkdf2 — Generates a PKCS5 v2 PBKDF2 string

Description

openssl_pbkdf2 ( string $password , string $salt , int $key_length , int $iterations [, string $digest_algorithm = "sha1" ] ) : string|false

openssl_pbkdf2() computes PBKDF2 (Password-Based Key Derivation Function 2), a key derivation function defined in PKCS5 v2.

Parameters

password

Password from which the derived key is generated.

salt

PBKDF2 recommends a crytographic salt of at least 64 bits (8 bytes).

key_length

Length of desired output key.

iterations

The number of iterations desired. » NIST recommends at least 10,000.

digest_algorithm

Optional hash or digest algorithm from openssl_get_md_methods(). Defaults to SHA-1.

Return Values

Returns raw binary string or false on failure.

Examples

Example #1 openssl_pbkdf2() example

<?php
$password = 'yOuR-pAs5w0rd-hERe';
$salt = openssl_random_pseudo_bytes(12);
$keyLength = 40;
$iterations = 10000;
$generated_key = openssl_pbkdf2($password, $salt, $keyLength, $iterations, 'sha256');
echo bin2hex($generated_key)."\n";
echo base64_encode($generated_key)."\n";
?>

See Also

© 1997–2020 The PHP Documentation Group
Licensed under the Creative Commons Attribution License v3.0 or later.
https://www.php.net/manual/en/function.openssl-pbkdf2.php