Secure Capacity Region for Erasure Broadcast Channels with Feedback
The authors formulate and explain a cryptographic problem relevant to wireless: a sender, Alice, wants to transmit private messages to two receivers, Bob and Calvin, using unreliable wireless broadcast transmissions and short public feedback from Bob and Calvin. They ask, at what rates can, they broadcast the private messages if they also provide (information-theoretic) unconditional security guarantees that Bob and Calvin do not learn each-other's message? they characterize the largest transmission rates to the two receivers, for any protocol that provides unconditional security guarantees. They design a protocol that operates at any rate-pair within the above region, uses very simple interactions and operations, and is robust to misbehaving users.