3v4l.org

run code in 300+ PHP versions simultaneously
<?php $password = 'zzzzzzzzzz'; do { $hash = hash_hmac('sha512', ++$password, 'some key'); } while(strpos($hash, "\0") === false); echo $password;
Output for 7.0.31, 7.1.20 - 7.1.21, 7.2.8 - 7.2.33, 7.3.16 - 7.3.33, 7.4.3 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6

Process exited with code 137.
preferences:
123.16 ms | 403 KiB | 144 Q