code: func CryptoRandomHex(len int) (string, error) {
  	randomBytes := make([]byte, len)
  	if _, err := rand.Reader.Read(randomBytes); err != nil {
  		return "", trace.Wrap(err)
  	}
  	return hex.EncodeToString(randomBytes), nil
  }
docs: // CryptoRandomHex returns hex encoded random string generated with crypto-strong
  // pseudo random generator of the given bytes