//  <HTTPMethod>\n
	//  <CanonicalURI>\n
	//  <CanonicalQueryString>\n
	//  <CanonicalHeaders>\n
	//  <SignedHeaders>\n
	//  <HashedPayload>
	//
	canonicalRequest := strings.Join([]string{
		req.Method,
		canonicalURI,
		req.URL.RawQuery,
		canonicalHeaders,
		signedHeaders,
		hashedPayload,
	}, "\n")

	// Get scope.
	scope := strings.Join([]string{
		currTime.Format(yyyymmdd),

    "groups": null,
    "action": "s3:ListBucket",
    "bucket": "test",
    "conditions": {
      "Authorization": [
        "AWS4-HMAC-SHA256 Credential=minio/20220507/us-east-1/s3/aws4_request, SignedHeaders=host;x-amz-content-sha256;x-amz-date, Signature=62012db6c47d697620cf6c68f0f45f6e34894589a53ab1faf6dc94338468c78a"
      ],
      "CurrentTime": [
        "2022-05-07T18:31:41Z"
      ],
      "Delimiter": [
        "/"

		return cred, "", "", time.Time{}, ErrContentSHA256Mismatch
	}

	// Extract all the signed headers along with its values.
	extractedSignedHeaders, errCode := extractSignedHeaders(signV4Values.SignedHeaders, r)
	if errCode != ErrNone {
		return cred, "", "", time.Time{}, errCode
	}

	cred, _, errCode = checkKeyValid(r, signV4Values.Credential.accessKey)
	if errCode != ErrNone {

		Description:    "Signature header missing Signature field.",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrMissingSignHeadersTag: {
		Code:           "InvalidArgument",
		Description:    "Signature header missing SignedHeaders field.",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrMalformedExpires: {
		Code:           "AuthorizationQueryParametersError",
		Description:    "X-Amz-Expires should be a number",

	req = signer.StreamingUnsignedV4(req, "", 8, now)

	maliciousHeaders := http.Header{
		"Authorization":                []string{fmt.Sprintf("AWS4-HMAC-SHA256 Credential=%s/%s/us-east-1/s3/aws4_request, SignedHeaders=invalidheader, Signature=deadbeefdeadbeefdeadbeeddeadbeeddeadbeefdeadbeefdeadbeefdeadbeef", s.accessKey, now.Format(yyyymmdd))},
		"User-Agent":                   []string{"A malicious request"},