/**
* Performs a HMAC computation given relevant details such as Key, Hashing
* algorithm, the data to compute MAC of, and an output format of String,
* Binary notation or BTWOC.
*
* @param string $key
* @param string $hash
* @param string $data
* @param string $output
* @param boolean $internal
* @return string
*/
public static function compute($key, $hash, $data, $output = self::STRING)
{
// set the key
if (!isset($key) || empty($key)) {
require_once 'Zend/Crypt/Hmac/Exception.php';
throw new Zend_Crypt_Hmac_Exception('provided key is null or empty');
}
self::$_key = $key;
// set the hash
self::_setHashAlgorithm($hash);
// perform hashing and return
return self::_hash($data, $output);
}
