README

PasswordHashingMachine is a tool for hashing and checking passwords using a required hashing algorithm, which must be registered from the outside.

More hashing algorithms can be registered to PasswordHashingMachine so legacy hashes can be also successfully handled.

Usage

1. Create the hashing machine

$hasher = new Yarri\PasswordHashingMachine();

2. Add one or more hashing algorithms

//  $hasher->addAlgorithm(
//    callback $hash_callback,
//    callback $is_hash_callback,
//    callback $check_password_callback,
//    callback $needs_rehash_callback
//  );

The first added algorithm is also the default hashing algorithm.

// default hashing algorithm - bcrypt
$hasher->addAlgorithm(
  function($password){ return password_hash($password,PASSWORD_BCRYPT); },
  function($hash){ return (bool)preg_match('/^\$2[aby]\$\d{2}\$[.\/0-9A-Za-z]{53}$/',$hash); },
  function($password,$hash){ return password_verify($password,$hash); },
  function($hash){ return password_needs_rehash($hash,PASSWORD_BCRYPT); }
);

The optional 4th callback $needs_rehash_callback tells PasswordHashingMachine that a hash, although produced by this very algorithm, is outdated (e.g. it uses a lower cost/round count than currently configured) and should be rehashed. When omitted, it defaults to always returning false.

Add any other legacy hashing algorithms you need in your application.

// algorithm for md5 hashes with common salt
$hasher->addAlgorithm(
  function($password){ return md5(SITE_KEY.$password); },
  function($password){ return preg_match('/^[0-9a-f]{32}$/',$password); },
  function($password,$hash){ return md5(SITE_KEY.$password) === $hash; }
);

// algorithm for md5 hashes
$hasher->addAlgorithm(
  function($password){ return md5($password); },
  function($password){ return preg_match('/^[0-9a-f]{32}$/',$password); },
  function($password,$hash){ return md5($password) === $hash; }
);

In fact, for algorithms that provide hexadecimal hashes like md5, sha1, sha2, only the first callback is required.

$hasher->addAlgorithm(
  function($password){ return sha1($password); }
);

3. Use the machine

// hashing passwords
$hasher->hash("secret"); // e.g. '$2a$06$rLxnps2CuGC/9BPCq3ms..7uaWETN6GPiVMXYYGWqdQoMZsDQ/kFG'
$hasher->hash('$2a$06$rLxnps2CuGC/9BPCq3ms..7uaWETN6GPiVMXYYGWqdQoMZsDQ/kFG'); // rehash! e.g. '$2y$10$XPuxlYvtelPKTpYtBpeAxOEuidftLo/kGkmmZgtWCFehvWz2N43wy'
$hasher->hash(""); // e.g. '$2y$10$FZQFYFamZjnrUr1XvIdGTevA.iLQNSYvHXrP3LETn67AEGreuYCwe'

// hashing password but preserving valid hashes or empty parameters
$hasher->filter("secret"); // e.g. '$2a$06$rLxnps2CuGC/9BPCq3ms..7uaWETN6GPiVMXYYGWqdQoMZsDQ/kFG'
$hasher->filter('$2a$06$rLxnps2CuGC/9BPCq3ms..7uaWETN6GPiVMXYYGWqdQoMZsDQ/kFG'); // '$2a$06$rLxnps2CuGC/9BPCq3ms..7uaWETN6GPiVMXYYGWqdQoMZsDQ/kFG'
$hasher->filter(""); // ""
$hasher->filter(null); // null

// checking hashes
$hasher->isHash($hash); // true
$hasher->isHash("something"); // false
$hasher->isHash(""); // false

// verifying passwords
$hasher->verify($password,$hash); // true or false

After a successful verification, the need for re-hashing can be detected and the password re-hashing using the current hashing algorithm can be easily realized. This is the case either when the hash comes from a legacy algorithm, or when it comes from the current algorithm but is outdated (e.g. lower round count).

$hash = $user->getPasswordHash();
if($hasher->verify($password,$hash,$need_rehash)){
  // the user is verified
  if($need_rehash){
     // transparent password re-hashing using the current hashing algorithm
     $current_hash = $hasher->hash($password);
     $user->setPasswordHash($current_hash);
  }
}

Installation

The best way how to install PasswordHashingMachine is to use the Composer:

composer require yarri/password-hashing-machine

Requires PHP 5.6 or newer.

License

PasswordHashingMachine is free software distributed under the terms of the MIT license

yarri / password-hashing-machine

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