wp_salt() │ WP 2.5.0

Get salt to add to hashes.

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.

Pluggable function — this function can be replaced from a plugin. It means that this function is defined (works) only after all plugins are loaded (included), but before this moment this function has not defined. Therefore, you cannot call this and all functions depended on this function directly from a plugin code. They need to be called on plugins_loaded hook or later, for example on init hook.

Function replacement (override) — in must-use or regular plugin you can create a function with the same name, then it will replace this function.

Hooks from the function

Return

String. Salt value

Usage

wp_salt( $scheme );
$scheme(string)
Authentication scheme (auth, secure_auth, logged_in, nonce).
Default: 'auth'

Examples

0

#1 Demonstration of wp_salt 

$salt = wp_salt('logged_in');
echo $salt;

// outputs something like this:
// 0D3*SIMO4$(t~I;E]NBx}L`Vy2U8o|{vbxH4t3l-!4-Io N(U74&+BdC^S,~*0^B>k,|4/`76[PG|V:)}o$)!hh1GgZ>t8[A-rmF&RDU~|fcN1/]T7i/=H

Changelog

Since 2.5.0 Introduced.

wp_salt() code WP 6.5.2

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,
		);

		/*
		 * translators: This string should only be translated if wp-config-sample.php is localized.
		 * You can check the localized release package or
		 * https://i18n.svn.wordpress.org/<locale code>/branches/<wp version>/dist/wp-config-sample.php
		 */
		$duplicated_keys[ __( '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 );
}

Security