Crypt::hashEquals

[benlamptey]

                if (!Crypt::hashEquals($hash, $cookie_hash)) {
                    throw new Exception(
                        'Cookie hash invalid. This indicates either tampering or an out of date drupal4ssp module.'
                    );
                }

hashEquals no longer exists in Drupal 9, and it has been suggested to use PHP's built-in function hash_equals
https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Component%21Utility%21Crypt.php/function/Crypt%3A%3AhashEquals/8.9.x

[benlamptey-gocity]

ignore - i can actually see this has been updated 2 years ago...must have been referencing an old version