What are the potential causes of discrepancies in the output of the crypt function across different platforms or installations?

The potential causes of discrepancies in the output of the crypt function across different platforms or installations include differences in the underlying hashing algorithms used by the crypt function, differences in the salt generation methods, and variations in the implementation of the crypt function itself. To ensure consistent output across platforms, it is recommended to specify the hashing algorithm and salt manually when using the crypt function.

$password = "password123";
$salt = '$2a$10$' . substr(str_replace('+', '.', base64_encode(random_bytes(22))), 0, 22);
$hashed_password = crypt($password, $salt);