Как проще всего и надежно хешировать пароль в PHP 5.3.5?
Всё давно в ядре: password_hash + password_verify
https://www.php.net/manual/en/function.password-ha...
тутcrypt('password', '$6$rounds=150000$PerUserCryptoRandomSalt$')
$6 - use SHA-512, which has 64-bit operations that reduce the margin of advantage most GPU based attackers have over you as of early 2016.
$rounds=150000 - set the number of iterations to hundreds of thousands or high tens of thousands of rounds.
PerUserCryptoRandomSalt - unlike password_hash, you have to do this yourself. You need to generate a unique, cryptographically random salt of 12-24 binary bytes (16 is very reasonable)