code: func constructCertFileName(cert *x509.Certificate) string {
  	// construct the filename as the CN with no period and space
  	name := strings.Replace(cert.Subject.CommonName, ".", "", -1)
  	name = strings.Replace(name, " ", "", -1)
  
  	// add SKI and serial number as extra identifier
  	name += fmt.Sprintf("_%x", cert.SubjectKeyId)
  	name += fmt.Sprintf("_%x", cert.SerialNumber.Bytes())
  
  	name += ".crt"
  	return name
  }
docs: // constructCertFileName returns a uniquely identifying file name for a certificate