Source

File: wp-includes/class-wp-recovery-mode-cookie-service.php

private function recovery_mode_hash( $data ) {
		if ( ! defined( 'AUTH_KEY' ) || AUTH_KEY === 'put your unique phrase here' ) {
			$auth_key = get_site_option( 'recovery_mode_auth_key' );

			if ( ! $auth_key ) {
				if ( ! function_exists( 'wp_generate_password' ) ) {
					require_once ABSPATH . WPINC . '/pluggable.php';
				}

				$auth_key = wp_generate_password( 64, true, true );
				update_site_option( 'recovery_mode_auth_key', $auth_key );
			}
		} else {
			$auth_key = AUTH_KEY;
		}

		if ( ! defined( 'AUTH_SALT' ) || AUTH_SALT === 'put your unique phrase here' || AUTH_SALT === $auth_key ) {
			$auth_salt = get_site_option( 'recovery_mode_auth_salt' );

			if ( ! $auth_salt ) {
				if ( ! function_exists( 'wp_generate_password' ) ) {
					require_once ABSPATH . WPINC . '/pluggable.php';
				}

				$auth_salt = wp_generate_password( 64, true, true );
				update_site_option( 'recovery_mode_auth_salt', $auth_salt );
			}
		} else {
			$auth_salt = AUTH_SALT;
		}

		$secret = $auth_key . $auth_salt;

		return hash_hmac( 'sha1', $data, $secret );
	}