return (!strings.HasPrefix(r.Header.Get(xhttp.Authorization), signV4Algorithm) &&
		strings.HasPrefix(r.Header.Get(xhttp.Authorization), signV2Algorithm))
}

// Verify if request has AWS PreSign Version '4'.
func isRequestPresignedSignatureV4(r *http.Request) bool {
	_, ok := r.Form[xhttp.AmzCredential]
	return ok
}

// Verify request has AWS PreSign Version '2'.
func isRequestPresignedSignatureV2(r *http.Request) bool {