- var_dump: documentation ( source)
- password_needs_rehash: documentation ( source)
- crypt: documentation ( source)
<?php
var_dump(password_needs_rehash(crypt('Example', '$1$'), PASSWORD_BCRYPT)); // CRYPT_MD5
var_dump(password_needs_rehash(crypt('Example', '$6$rounds=5000$aa$'), PASSWORD_BCRYPT)); // CRYPT_SHA512 with 5000 rounds