/**
* Decide on the best acceptable hash algorithm we have available for hash()
* @return string A hash algorithm
*/
public static function hashAlgo()
{
if (!is_null(self::$algo)) {
return self::$algo;
}
$algos = hash_algos();
$preference = ['whirlpool', 'sha256', 'sha1', 'md5'];
foreach ($preference as $algorithm) {
if (in_array($algorithm, $algos)) {
self::$algo = $algorithm;
return self::$algo;
}
}
// We only reach here if no acceptable hash is found in the list, this should
// be a technical impossibility since most of php's hash list is fixed and
// some of the ones we list are available as their own native functions
// But since we already require at least 5.2 and hash() was default in
// 5.1.2 we don't bother falling back to methods like sha1 and md5.
throw new DomainException("Could not find an acceptable hashing function in hash_algos()");
}
