Laravel: Implementing a CRYPT_SHA512 Hasher

In this article we will create an implementation of Illuminate\Contracts\Hashing\Hasher using PHP's crypt function and the CRYPT_SHA512 hashing function. Like in the previous sections, we will examine each method before looking at the full implementation.

make($value, array $options = [])

The make method is responsible for doing the actual hashing. It accepts an $options array. We will allow a sixteen character long salt to be supplied using the options array. If no salt is supplied, we will generate one. We will also accept a rounds option, to control the number of iterations the hashing function will perform.

For the actual hashing, we will make a call to PHP's crypt function.

public function check($value, $hashedValue, array $options = [])

The check method is used to check that a known $value is the same as a given $hashedValue. We will not need any options for this method.

For the actual hashing, we will use PHP's crypt function.

public function needsRehash($hashedValue, array $options = [])

The needsRehash method is used to determine if a given hash needs to be updated, or rehashed. We will accept a salt as an option. If the salt from the $options array does not match the salt from the $hashedValue the $hashedValue, or if the rounds from the $options array does not match the rounds from the $hashedValue, the $hashedValue needs to be rehashed.

The following is the complete implementation of the Sha512Hasher class. Because implementing CRYPT_SHA512 is almost identical to implementing CRYPT_SHA256, and because the Sha256Hasher class gets the value for the hashing function from the protected $shaPrefix variable, we can simple extend the Sha256Hasher class and make a simple change:

 1<?php
 2 
 3namespace Laravel\Artisan\Hashing;
 4 
 5use Illuminate\Contracts\Hashing\Hasher as HasherContract;
 6 
 7class Sha512Hasher extends Sha256Hasher implements HasherContract
 8{
 9 
10    /**
11     * The prefix expected by the crpyt function.
12     *
13     * Changed to match the SHA-512 hashing function
14     * prefix that can be found in the PHP docs at
15     * http://php.net/manual/en/function.crypt.php
16     *
17     * @var string
18     */
19    protected $shaPrefix = '6';
20 
21}

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