(WIP) add ability to invite others to a group

[mixmix]

Requires:

• derive shared-dm-key

  • make a test vector for private-group-spec
  • write a function for generating these
  • make sure it includes key scheme

• using shared-dm-key

  • include a cache
  • for unboxing, add to key-store#author.getKeys()
    • decide if this key should be before / after group keys
  • for boxing, make sure cache is also accessible

• make unbox3 test vector to cover envelope to a DM

• write method/group/invite (with test)

  • decide where the members tangle starts at
    • (a) group init?
    • (b) first add-member? << I think this one will make backlink lookups quicker, but how do we know which is the canonical members tangle ?
  • calculate heads of members tangle
  • calculate heads of group tangle

• add maxAttempts to private-group-spec

• re-index :

  • watch for receipt of group invite, reindex if a new one shows up
  • decide which views to destroy
  • can an add-member be sent to another group?
    • NOTE a group needs to know all recipients to work (because of how we try unboxing). Therefore this only works in the case where you start a subgroup which is totally visible to parent group. (this ensures all subgroup members are known)
    • don't do this now >:(
    • YES - in the case of a subgroup visible to parent group (a

[mixmix]

thanks for watching @cryptix !
god, I thought "I'd better just make a little checklist before I got to bed". Turns out there are some kinda hard problems hidden in here. Sigh