//  	[ subresource, if present. For example "?acl", "?location", "?logging", or "?torrent"];
//
// CanonicalizedProtocolHeaders = <described below>

// doesSignV2Match - Verify authorization header with calculated header in accordance with
//     - http://docs.aws.amazon.com/AmazonS3/latest/dev/auth-request-sig-v2.html

}

// Verify if request has valid AWS Signature Version '2'.
func isReqAuthenticatedV2(r *http.Request) (s3Error APIErrorCode) {
	if isRequestSignatureV2(r) {
		return doesSignV2Match(r)
	}
	return doesPresignV2SignatureMatch(r)
}

func reqSignatureV4Verify(r *http.Request, region string, stype serviceType) (s3Error APIErrorCode) {
	sha256sum := getContentSha256Cksum(r, stype)
	switch {