code: func (k *Key) String() string {
  	s := string(k.Format) + " " + base64.StdEncoding.EncodeToString(k.Blob)
  
  	if k.Comment != "" {
  		s += " " + k.Comment
  	}
  
  	return s
  }
docs: // String returns the storage form of an agent key with the format, base64
  // encoded serialized key, and the comment if it is not empty.