public static function getDigest($digestName)
    {
        $enzymes = self::getEnzymes();
        $digestUp = strtoupper($digestName);
        
        foreach (array_keys($enzymes) as $key) {
            if (strtoupper($key) == $digestUp) {
                $classPath = __NAMESPACE__ . '\\Digest' . $key;
                return new $classPath();
            }
        }
        
        throw new \InvalidArgumentException('Unknown digest algorithm - ' . $digestName);
    }