region := globalSite.Region
	date := UTCNow()
	scope := getScope(date, region)
	credential := fmt.Sprintf("%s/%s", accessKeyID, scope)

	// Set URL query.
	query := req.URL.Query()
	query.Set("X-Amz-Algorithm", signV4Algorithm)
	query.Set("X-Amz-Date", date.Format(iso8601Format))
	query.Set("X-Amz-Expires", strconv.FormatInt(expires, 10))
	query.Set("X-Amz-SignedHeaders", "host")
	query.Set("X-Amz-Credential", credential)