README.md

Creating a group

This is a spec for how to initialise a new group.

⚠️ schema.json is generated so don't modify it directly

Group init root example

Notably, the first message does not have a recps field with this group_id in it, because the definition of group_id depends on the key of this message, which will not be known until this is published.

This means this initial message and it's content will need to be manually boxed, with the recipient_keys being the symmetric group_key for this new group as well as to your own_key, for recovery purposes.

Do not be tempted to overload this initialisation message. Adding people to the group would interfere with the add-member spec

Here's how you initialise a group in the current JS stack

// assume you already know your feedId + prevMsgId for this feed
var feedId = 'ssb:feed/bendybutt-v1/-oaWWDs8g73EZFUMfW37R_ULtFEjwKN_DczvdYihjbU='
var prevMsgId = 'ssb:message/classic/Zz-Inkte70Qz1UVKUHIhOgo16Oj_n37PfgmIzLDBgZw=.sha256'

var feed_id = ... BFE binary encoding of feed_id
var prev_msg_id = ... BFE binary encoding of feed_id

var group_secret = {
  key: group_buffer, // group_buffer is symmetric key as buffer
  scheme: 'envelope-large-symmetric-group'
}
var own_key = {
  key: own_buffer, // own_buffer is a symmetric key as a buffer
  scheme: 'envelope-symmetric-key-for-self'
}
var msg_key =  ... make up a one use key for the msg as a buffer

// here's the unencrypted init message
var plainText = {
  type: 'group/init'
  version: 'v2',
  secret: group_secret.toString('base64'),
  tangles: {
    group: {
      root: null,
      previous: null
    },
    epoch: {
      root: null,
      previous: null
    }
    members: {
      root: null,
      previous: null
    }
  }
}

var plain_text = .... stringify + buffer

var ciphertext = envelope(plain_text, feed_id, prev_msg_id, msg_key, [ group_key, own_key ])

// what you publish (enveloped plaintext)
// ciphertext = "SDSDsadlksajda432wdfsdlkfja=.box2"