Document the protocol & algorithms in more detail:

• architecture
  • core vs edge/local broker, verifier, apps, clients, UI
  • node services
• broker
  • BranchSyncReq
    • heads known by requestor, responder can answer without decrypting anything
  • BranchHeadsReq
    • keep track of heads in a topic
  • ExtRequest
    • how to compute MAC?
  • how to get rid of invalid commits?
• verifier
  • verify after all deps are available
  • keep track of verified heads
  • discard invalid commits