<?php
/**
* Zend Framework (http://framework.zend.com/)
*
* @link http://github.com/zendframework/zf2 for the canonical source repository
* @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
namespace Zend\Crypt;
/**
* PHP implementation of the RFC 2104 Hash based Message Authentication Code
*/
class Hmac
{
const OUTPUT_STRING = false;
const OUTPUT_BINARY = true;
/**
* Last algorithm supported
*
* @var string|null
*/
protected static $lastAlgorithmSupported;
/**
* Performs a HMAC computation given relevant details such as Key, Hashing
* algorithm, the data to compute MAC of, and an output format of String,
* or Binary.
*
* @param string $key
* @param string $hash
* @param string $data
* @param bool $output
* @throws Exception\InvalidArgumentException
* @return string
*/
public static function compute($key, $hash, $data, $output = self::OUTPUT_STRING)
{
if (empty($key)) {
throw new Exception\InvalidArgumentException('Provided key is null or empty');
}
if (!$hash || ($hash !== static::$lastAlgorithmSupported && !static::isSupported($hash))) {
throw new Exception\InvalidArgumentException(
"Hash algorithm is not supported on this PHP installation; provided '{$hash}'"
);
}
return hash_hmac($hash, $data, $key, $output);
}
/**
* Get the output size according to the hash algorithm and the output format
*
* @param string $hash
* @param bool $output
* @return int
*/
public static function getOutputSize($hash, $output = self::OUTPUT_STRING)
{
return strlen(static::compute('key', $hash, 'data', $output));
}
/**
* Get the supported algorithm
*
* @return array
*/
public static function getSupportedAlgorithms()
{
return hash_algos();
}
/**
* Is the hash algorithm supported?
*
* @param string $algorithm
* @return bool
*/
public static function isSupported($algorithm)
{
if ($algorithm === static::$lastAlgorithmSupported) {
return true;
}
if (in_array(strtolower($algorithm), hash_algos(), true)) {
static::$lastAlgorithmSupported = $algorithm;
return true;
}
return false;
}
/**
* Clear the cache of last algorithm supported
*/
public static function clearLastAlgorithmCache()
{
static::$lastAlgorithmSupported = null;
}
}