Still no progress

Things to Note down

1. User authentication based on PKI
2. Shared key 
1. used for enc of user messages
2. join/leave or expire causes regeneration
3. leader generates those
3. Leader election - based on age?
4. History never stored in servers; only at senders and receivers

Enc mechanisms
Join/Leave messages - enc with PKI
User messages - enc with shared key

Expectation:
# of Join/Leave msgs <<< User messages

Not quite sure how Leader election happens? May be age is used?