}

// Check to see if Policy is signed correctly.
func doesPolicySignatureMatch(formValues http.Header) (auth.Credentials, APIErrorCode) {
	// For SignV2 - Signature field will be valid
	if _, ok := formValues[xhttp.AmzSignatureV2]; ok {
		return doesPolicySignatureV2Match(formValues)
	}
	return doesPolicySignatureV4Match(formValues)
}

// compareSignatureV4 returns true if and only if both signatures