password_compat =============== [![Build Status](https://travis-ci.org/ircmaxell/password_compat.png?branch=master)](https://travis-ci.org/ircmaxell/password_compat) This library is intended to provide forward compatibility with the password_* functions being worked on for PHP 5.5. See [the RFC](https://wiki.php.net/rfc/password_hash) for more detailed information. Requirements ============ This library requires `PHP >= 5.3.7` OR a version that has the `$2y` fix backported into it (such as Debian provides). The runtime checks have been removed due to this version issue. To see if password_compat is available for your system, run the included `version-test.php`. If it outputs "Pass", you can safely use the library. If not, you cannot. If you attempt to use password-compat on an unsupported version, attempts to create or verify hashes will return `false`. You have been warned! The reason for this is that PHP prior to 5.3.7 contains a security issue with its BCRYPT implementation. Therefore, it's highly recommended that you upgrade to a newer version of PHP prior to using this layer. Installation ============ To install, simply `require` the `password.php` file under `lib`. You can also install it via `Composer` by using the [Packagist archive](http://packagist.org/packages/ircmaxell/password-compat). Usage ===== **Creating Password Hashes** To create a password hash from a password, simply use the `password_hash` function. $hash = password_hash($password, PASSWORD_BCRYPT); Note that the algorithm that we chose is `PASSWORD_BCRYPT`. That's the current strongest algorithm supported. This is the `BCRYPT` crypt algorithm. It produces a 60 character hash as the result. `BCRYPT` also allows for you to define a `cost` parameter in the options array. This allows for you to change the CPU cost of the algorithm: $hash = password_hash($password, PASSWORD_BCRYPT, ["cost" => 10]); That's the same as the default. The cost can range from `4` to `31`. I would suggest that you use the highest cost that you can, while keeping response time reasonable (I target between 0.1 and 0.5 seconds for a hash, depending on use-case). Another algorithm name is supported: PASSWORD_DEFAULT This will use the strongest algorithm available to PHP at the current time. Presently, this is the same as specifying `PASSWORD_BCRYPT`. But in future versions of PHP, it may be updated to use a stronger algorithm if one is introduced. It can also be changed if a problem is identified with the BCRYPT algorithm. Note that if you use this option, you are **strongly** encouraged to store it in a `VARCHAR(255)` column to avoid truncation issues if a future algorithm increases the length of the generated hash. It is very important that you should check the return value of `password_hash` prior to storing it, because a `false` may be returned if it encountered an error. **Verifying Password Hashes** To verify a hash created by `password_hash`, simply call: if (password_verify($password, $hash)) { /* Valid */ } else { /* Invalid */ } That's all there is to it. **Rehashing Passwords** From time to time you may update your hashing parameters (algorithm, cost, etc). So a function to determine if rehashing is necessary is available: if (password_verify($password, $hash)) { if (password_needs_rehash($hash, $algorithm, $options)) { $hash = password_hash($password, $algorithm, $options); /* Store new hash in db */ } }