hash.Write(data)
	return hash.Sum(nil)
}

// extractSignedHeaders extract signed headers from Authorization header
func extractSignedHeaders(signedHeaders []string, r *http.Request) (http.Header, APIErrorCode) {
	reqHeaders := r.Header
	reqQueries := r.Form
	// find whether "host" is part of list of signed headers.
	// if not return ErrUnsignedHeaders. "host" is mandatory.

	claims, _ := getClaimsFromToken(getSessionToken(r))
	return claims
}

func getClaimsFromTokenWithSecret(token, secret string) (map[string]interface{}, error) {
	// JWT token for x-amz-security-token is signed with admin
	// secret key, temporary credentials become invalid if
	// server admin credentials change. This is done to ensure
	// that clients cannot decode the token using the temp

		Description:    "Your key is too long",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrUnsignedHeaders: {
		Code:           "AccessDenied",
		Description:    "There were headers present in the request which were not signed",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrInvalidQueryParams: {
		Code:           "AuthorizationQueryParametersError",

	}

	// Since the list of signed headers value contained `expect`, the default value of `100-continue` will be added to extracted signed headers.
	if extractedExpect != expectedExpect {
		t.Errorf("expect header incorrect value: expected `%s`, got `%s`", expectedExpect, extractedExpect)
	}

	// case where the headers don't contain the one of the signed header in the signed headers list.

// Excerpts from @lsegal - https://github.com/aws/aws-sdk-js/issues/659#issuecomment-120477258
//
//	User-Agent:
//
//	    This is ignored from signing because signing this causes problems with generating pre-signed URLs
//	    (that are executed by other agents) or when customers pass requests through proxies, which may
//	    modify the user-agent.
//
//	Authorization:
//
//	    Is skipped for obvious reasons

				"X-Amz-Content-Sha256": payloadSHA256,
			},
			region:   "us-west-1",
			expected: ErrUnsignedHeaders,
		},
		// (3) Should fail to extract headers if the host header is not signed.
		{
			queryParams: map[string]string{
				"X-Amz-Algorithm":      signV4Algorithm,
				"X-Amz-Date":           now.Format(iso8601Format),
				"X-Amz-Expires":        "60",

		{
			authT: authTypePresigned,
			pass:  true,
		},
		// Test 3 - supported s3 type signed.
		{
			authT: authTypeSigned,
			pass:  true,
		},
		// Test 4 - supported s3 type with post policy.
		{
			authT: authTypePostPolicy,
			pass:  true,
		},
		// Test 5 - supported s3 type with streaming signed.
		{
			authT: authTypeStreamingSigned,
			pass:  true,
		},

		return "", ErrMissingSignTag
	}
	if signFields[1] == "" {
		return "", ErrMissingFields
	}
	signature := signFields[1]
	return signature, ErrNone
}

// Parse slice of signed headers from signed headers tag.
func parseSignedHeader(signedHdrElement string) ([]string, APIErrorCode) {
	signedHdrFields := strings.Split(strings.TrimSpace(signedHdrElement), "=")
	if len(signedHdrFields) != 2 {

	if payload != req.Header.Get(xhttp.AmzContentSha256) {
		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
	}

}

func getReqAccessKeyV2(r *http.Request) (auth.Credentials, bool, APIErrorCode) {
	if accessKey := r.Form.Get(xhttp.AmzAccessKeyID); accessKey != "" {
		return checkKeyValid(r, accessKey)
	}

	// below is V2 Signed Auth header format, splitting on `space` (after the `AWS` string).
	// Authorization = "AWS" + " " + AWSAccessKeyId + ":" + Signature
	authFields := strings.Split(r.Header.Get(xhttp.Authorization), " ")
	if len(authFields) != 2 {