[MLS] [Delivery Service]

[Pascal Junod <[e-mail]>]

Hi !

In the architecture document, one expects the Delivery Service "*to route
messages between clients and to act as a message broadcaster, taking in one
message and forwarding it to multiple clients (also known as “server side
fanout”).*" (cf. §2.3)

At the same time, a bit further, one can read that "*Group membership is
itself sensitive information and MLS is designed so that neither the DS nor
the AS need have static knowledge of which clients are in which group.*"

In particular, the ClientInitKey and Welcome messages do not have any
notion about group or node identities, they only have the client_init_key_id
field in common, which means that the DS has no means (through the current
protocol format) to route messages in a proper way.

How is it possible to solve this apparent contradiction ?

Many thanks in advance,

Pascal