CI_Encryption::_openssl_decrypt PHP Method

    protected function _openssl_decrypt($data, $params)
    {
        if ($iv_size = openssl_cipher_iv_length($params['handle'])) {
            $iv = self::substr($data, 0, $iv_size);
            $data = self::substr($data, $iv_size);
        } else {
            $iv = NULL;
        }
        return empty($params['handle']) ? FALSE : openssl_decrypt($data, $params['handle'], $params['key'], 1, $iv);
    }