=== Leave ===
Leaving a chatroom involves only one procedure for those who are staying in the chatroom (Procedure Farewell) which is described in Algorithm [[mpCAT#Farewell|4]]. The remaining participants only need a notice from the server that the user is leaving to re-run the one round key update algorithm. Also, failure to receive a heartbeat from a user will result in executing Algorithm [[mpCAT#Farewell|4]] excluding users which did not update their key.
====Farewell====