Trace and Revoke Schemes

Broadcast encryption of Chapter 2 deals with the problem of revocation for stateless receivers; the general context is a “sender to many receivers” transmission system that offers the ability for the sender to exclude a subset of the receivers from a certain transmission on demand. The statelessness of the receivers refers to the fact that receivers need not maintain state from one transmission to the next (and this enables them to go arbitrarily off-line without loosing their reception capability in the long run).