protected function hasherProviderFactory($config){
        $hasher  = $config['hasher'];
        switch ($hasher)
        {
            case 'native':
                return new NativeHasher;
                break;

            case 'bcrypt':
                return new BcryptHasher;
                break;

            case 'sha256':
                return new Sha256Hasher;
                break;

            case 'whirlpool':
                return new WhirlpoolHasher;
                break;
        }

        throw new \InvalidArgumentException("Invalid hasher [$hasher] chosen for Sentry.");
    }