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 {
	case isRequestSignatureV4(r):

		if s3Error = isReqAuthenticatedV2(r); s3Error != ErrNone {
			writeErrorResponse(ctx, w, errorCodes.ToAPIErr(s3Error), r.URL)
			return
		}
	case authTypePresigned, authTypeSigned:
		if s3Error = reqSignatureV4Verify(r, globalSite.Region(), serviceS3); s3Error != ErrNone {
			writeErrorResponse(ctx, w, errorCodes.ToAPIErr(s3Error), r.URL)
			return
		}

		if !skipContentSha256Cksum(r) {

		s3Err = isReqAuthenticatedV2(r)
		if s3Err != ErrNone {
			writeErrorResponse(ctx, w, errorCodes.ToAPIErr(s3Err), r.URL)
			return
		}

	case authTypePresigned, authTypeSigned:
		if s3Err = reqSignatureV4Verify(r, globalSite.Region(), serviceS3); s3Err != ErrNone {
			writeErrorResponse(ctx, w, errorCodes.ToAPIErr(s3Err), r.URL)
			return
		}
		if !skipContentSha256Cksum(r) {