wp_salt( string $scheme = 'auth' )

Returns a salt to add to hashes.

Description

Salts are created using secret keys. Secret keys are located in two places: in the database and in the wp-config.php file. The secret key in the database is randomly generated and will be appended to the secret keys in wp-config.php.

The secret keys in wp-config.php should be updated to strong, random keys to maximize security. Below is an example of how the secret key constants are defined. Do not paste this example directly into wp-config.php. Instead, have a secret key created just for you.

define('AUTH_KEY',         ' Xakm<o xQy rw4EMsLKM-?!T+,PFF})H4lzcW57AF0U@N@< >M%G4Yt>f`z]MON');
define('SECURE_AUTH_KEY',  'LzJ}op]mr|6+![P}Ak:uNdJCJZd>(Hx.-Mh#Tz)pCIU#uGEnfFz|f ;;eU%/U^O~');
define('LOGGED_IN_KEY',    '|i|Ux`9<p-h$aFf(qnT:sDO:D1P^wZ$$/Ra@miTJi9G;ddp_<q}6H1)o|a +&JCM');
define('NONCE_KEY',        '%:R{[P|,s.KuMltH5}cI;/k<Gx~j!f0I)m_sIyu+&NJZ)-iO>z7X>QYR0Z_XnZ@|');
define('AUTH_SALT',        'eZyT)-Naw]F8CwA*VaW#q*|.)g@o}||wf~@C-YSt}(dh_r6EbI#A,y|nU2{B#JBW');
define('SECURE_AUTH_SALT', '!=oLUTXh,QW=H `}`L|9/^4-3 STz},T(w}W<I`.JjPi)<Bmf1v,HpGe}T1:Xt7n');
define('LOGGED_IN_SALT',   '+XSqHc;@Q*K_b|Z?NC[3H!!EONbh.n<+=uKR:>*c(u`g~EJBf#8u#R{mUEZrozmm');
define('NONCE_SALT',       'h`GXHhD>SLWVfg1(1(N{;.V!MoE(SfbA_ksP@&`+AycHcAV$+?@3q+rxV{%^VyKT');

Salting passwords helps against tools which has stored hashed values of common dictionary strings. The added values makes it harder to crack.

Parameters

$scheme

(string) (Optional) Authentication scheme (auth, secure_auth, logged_in, nonce)

Default value: 'auth'

Return

(string) Salt value

More Information

Usage:
wp_salt( $scheme );
Notes:

Source

File: wp-includes/pluggable.php 

function wp_salt( $scheme = 'auth' ) {
		static $cached_salts = array();
		if ( isset( $cached_salts[ $scheme ] ) ) {
			/**
			 * Filters the WordPress salt.
			 *
			 * @since 2.5.0
			 *
			 * @param string $cached_salt Cached salt for the given scheme.
			 * @param string $scheme      Authentication scheme. Values include 'auth',
			 *                            'secure_auth', 'logged_in', and 'nonce'.
			 */
			return apply_filters( 'salt', $cached_salts[ $scheme ], $scheme );
		}

		static $duplicated_keys;
		if ( null === $duplicated_keys ) {
			$duplicated_keys = array( 'put your unique phrase here' => true );
			foreach ( array( 'AUTH', 'SECURE_AUTH', 'LOGGED_IN', 'NONCE', 'SECRET' ) as $first ) {
				foreach ( array( 'KEY', 'SALT' ) as $second ) {
					if ( ! defined( "{$first}_{$second}" ) ) {
						continue;
					}
					$value                     = constant( "{$first}_{$second}" );
					$duplicated_keys[ $value ] = isset( $duplicated_keys[ $value ] );
				}
			}
		}

		$values = array(
			'key'  => '',
			'salt' => '',
		);
		if ( defined( 'SECRET_KEY' ) && SECRET_KEY && empty( $duplicated_keys[ SECRET_KEY ] ) ) {
			$values['key'] = SECRET_KEY;
		}
		if ( 'auth' === $scheme && defined( 'SECRET_SALT' ) && SECRET_SALT && empty( $duplicated_keys[ SECRET_SALT ] ) ) {
			$values['salt'] = SECRET_SALT;
		}

		if ( in_array( $scheme, array( 'auth', 'secure_auth', 'logged_in', 'nonce' ), true ) ) {
			foreach ( array( 'key', 'salt' ) as $type ) {
				$const = strtoupper( "{$scheme}_{$type}" );
				if ( defined( $const ) && constant( $const ) && empty( $duplicated_keys[ constant( $const ) ] ) ) {
					$values[ $type ] = constant( $const );
				} elseif ( ! $values[ $type ] ) {
					$values[ $type ] = get_site_option( "{$scheme}_{$type}" );
					if ( ! $values[ $type ] ) {
						$values[ $type ] = wp_generate_password( 64, true, true );
						update_site_option( "{$scheme}_{$type}", $values[ $type ] );
					}
				}
			}
		} else {
			if ( ! $values['key'] ) {
				$values['key'] = get_site_option( 'secret_key' );
				if ( ! $values['key'] ) {
					$values['key'] = wp_generate_password( 64, true, true );
					update_site_option( 'secret_key', $values['key'] );
				}
			}
			$values['salt'] = hash_hmac( 'md5', $scheme, $values['key'] );
		}

		$cached_salts[ $scheme ] = $values['key'] . $values['salt'];

		/** This filter is documented in wp-includes/pluggable.php */
		return apply_filters( 'salt', $cached_salts[ $scheme ], $scheme );
	}

Uses

Uses Description
wp-includes/pluggable.php: wp_generate_password()

Generates a random password drawn from the defined set of characters.
wp-includes/pluggable.php: salt

Filters the WordPress salt.
wp-includes/plugin.php: apply_filters()

Calls the callback functions that have been added to a filter hook.
wp-includes/option.php: update_site_option()

Updates the value of an option that was already added for the current network.
wp-includes/option.php: get_site_option()

Retrieve an option value for the current network based on name of option.

Used By

Used By Description
wp-includes/pluggable.php: wp_hash()

Get hash of given string.

Changelog

Version Description
2.5.0 Introduced.

© 2003–2021 WordPress Foundation
Licensed under the GNU GPLv2+ License.
https://developer.wordpress.org/reference/functions/wp_salt