func doesPolicySignatureV4Match(formValues http.Header) (auth.Credentials, APIErrorCode) {
	// Server region.
	region := globalSite.Region()

	// Parse credential tag.
	credHeader, s3Err := parseCredentialHeader("Credential="+formValues.Get(xhttp.AmzCredential), region, serviceS3)
	if s3Err != ErrNone {
		return auth.Credentials{}, s3Err
	}

	r := &http.Request{Header: formValues}

				sampleTimeStr,
				"us-west-1",
				"s3",
				"aws4_request"),
			expectedErrCode: ErrNone,
		},
	}

	for i, testCase := range testCases {
		actualCredential, actualErrCode := parseCredentialHeader(testCase.inputCredentialStr, "us-west-1", "s3")
		// validating the credential fields.
		if testCase.expectedErrCode != actualErrCode {