req.URL.RawQuery += "&Signature=" + url.QueryEscape(signature)
	return nil
}

// Sign given request using Signature V2.
func signRequestV2(req *http.Request, accessKey, secretKey string) error {
	signer.SignV2(*req, accessKey, secretKey, false)
	return nil
}

// Sign given request using Signature V4.
func signRequestV4(req *http.Request, accessKey, secretKey string) error {
	// Get hashed payload.