moth/doc/philosophy.md

Philosophy

Some scattered thoughts by the architect, Neale.

Hardening

People are going to try to break this thing. It needs to be bulletproof. This pretty much set the entire design:

• As much as possible is done client-side
  • Participants can attack their own web browsers as much as they feel like
  • Also reduces server load
  • We even made a puzzle category to walk people through creating brute-force attacks!
    • Your laptop is faster than our server
    • We give you the carrot of hashed answers and the hashing function
    • This removes one incentive to DoS the server
• Generate static content whenever possible
  • Puzzles must be statically compiled before the event even starts
  • As much content as possible is generated by a maintenance loop
• Minimize dynamic handling
  • There are only three (3) dynamic handlers
    • team registration
    • answer validation
    • server state (open puzzles + event log)
  • You can disable team registration if you want, just remove teamids.txt
  • I even removed token handling once I realized we replicate the user experience with the answer handler and some client-side JavaScript
• As much as possible is read-only
  • The only read-write directory is state
  • This plays very well with Docker, which didn't exist when we designed MOTH
• Server code should be as tiny as possible
  • Server should provide highly limited functionality
  • It should be easy to remember in your head everything it does
• Server is also compiled
  • Static type-checking helps assure no run-time errors
• Server only tracks who scored how many points at what time
  • This means the scoreboard program determines rankings
  • Want to provide a time bonus for quick answers? I don't, but if you do, you can just modify the scoreboard to do so.
  • Maybe you want to show a graph of team rankings over time: just replay the event log.
  • Want to do some analysis of what puzzles take the longest to answer? It's all there.

Fairness

We spend a lot of time thinking about whether new content is going to feel fair. Or, more importantly, if there's a possibility for it to be viewed as unfair.

It's possible to run fun events that don't focus so much on fairness, but those aren't the type of events we run.

• People generally don't mind discovering that they could improve
• People can get furious if they feel like some system is unfairly targeting them
• Every team that does the same amount of work should have the same score
  • No time bonuses / decaying points
  • No penalties for trying things that don't work out
• No one should ever feel like it's impossible to catch up
  • Achievements ("cheevos") work well here
  • Time-based awards (flags) don't mesh with this idea