sodium_crypto_pwhash

(PHP 7 >= 7.2.0)

sodium_crypto_pwhash — Derive a key from a password

Description

sodium_crypto_pwhash ( int $length , string $password , string $salt , int $opslimit , int $memlimit [, int $alg ] ) : string

This function provides low-level access to libsodium's crypto_pwhash key derivation function. Unless you have specific reason to use this function, you should use sodium_crypto_pwhash_str() or password_hash() functions instead.

PHP: sodium_crypto_pwhash - Manual Home of Manuel PHP Contents Haut

Parameters

length: integer; The length of the password hash to generate, in bytes.
password: string; The password to generate a hash for.
salt: string A salt to add to the password before hashing. The salt should be unpredictable, ideally generated from a good random mumber source such as random_bytes(), and have a length of at least SODIUM_CRYPTO_PWHASH_SALTBYTES bytes.
opslimit: Represents a maximum amount of computations to perform. Raising this number will make the function require more CPU cycles to compute a key. There are some constants available to set the operations limit to appropriate values depending on intended use, in order of strength: SODIUM_CRYPTO_PWHASH_OPSLIMIT_INTERACTIVE, SODIUM_CRYPTO_PWHASH_OPSLIMIT_MODERATE and SODIUM_CRYPTO_PWHASH_OPSLIMIT_SENSITIVE.
memlimit: The maximum amount of RAM that the function will use, in bytes. There are constants to help you choose an appropriate value, in order of size: SODIUM_CRYPTO_PWHASH_MEMLIMIT_INTERACTIVE, SODIUM_CRYPTO_PWHASH_MEMLIMIT_MODERATE, and SODIUM_CRYPTO_PWHASH_MEMLIMIT_SENSITIVE. Typically these should be paired with the matching opslimit values.
alg: integer A number indicating the hash algorithm to use. By default SODIUM_CRYPTO_PWHASH_ALG_DEFAULT (the currently recommended algorithm, which can change from one version of libsodium to another), or explicitly using SODIUM_CRYPTO_PWHASH_ALG_ARGON2ID13, representing the Argon2id algorithm version 1.3.

PHP: sodium_crypto_pwhash - Manual Home of Manuel PHP Contents Haut

Return Values

Returns the derived key, or FALSE on failure. The return value is a binary string of the hash, not an ASCII-encoded representation, and does not contain additional information about the parameters used to create the hash, so you will need to keep that information if you are ever going to verify the password in future. Use sodium_crypto_pwhash_str() to avoid needing to do all that.

PHP: sodium_crypto_pwhash - Manual Home of Manuel PHP Contents Haut

Examples

Example #1 password_hash() example


<?php
//Need to keep the salt if we're ever going to be able to check this password
$salt = random_bytes(SODIUM_CRYPTO_PWHASH_SALTBYTES);
//Using bin2hex to keep output readable
echo bin2hex(
    sodium_crypto_pwhash(
        16, // == 128 bits
        'password',
        $salt,
        SODIUM_CRYPTO_PWHASH_OPSLIMIT_INTERACTIVE,
        SODIUM_CRYPTO_PWHASH_MEMLIMIT_INTERACTIVE,
        SODIUM_CRYPTO_PWHASH_ALG_ARGON2ID13
    )
);
?>

The above example will output something similar to:

a18f346ba57992eb7e4ae6abf3fd30ee

Find a PHP function

English translation

You have asked to visit this site in English. For now, only the interface is translated, but not all the content yet.

If you want to help me in translations, your contribution is welcome. All you need to do is register on the site, and send me a message asking me to add you to the group of translators, which will give you the opportunity to translate the pages you want. A link at the bottom of each translated page indicates that you are the translator, and has a link to your profile.

Thank you in advance.

Document created the 30/01/2003, last modified the 26/10/2018
Source of the printed document:https://www.gaudry.be/en/php-rf-function.sodium-crypto-pwhash.html

The infobrol is a personal site whose content is my sole responsibility. The text is available under CreativeCommons license (BY-NC-SA). More info on the terms of use and the author.

References

Manuel PHP : http://php.net

These references and links indicate documents consulted during the writing of this page, or which may provide additional information, but the authors of these sources can not be held responsible for the content of this page.
The author This site is solely responsible for the way in which the various concepts, and the freedoms that are taken with the reference works, are presented here. Remember that you must cross multiple source information to reduce the risk of errors.

Contents Haut