Dealing with packet loss in the Interactive Chained Stream Authentication protocol

This paper presents an improvement to the Interactive Chained Stream Authentication (I-CSA) protocol which is an efficient protocol useful to authenticate multicast transmissions over a network. The lockstep behavior intrinsic in its structure for data exchange may produce deadlocks, but not security breaches, in case the authentication information of the protocol is destroyed or modified by an intruder. The solution proposed (Enhanced I-CSA) introduces some modifications to the I-CSA protocol. This solution allows the parties involved in the transmission to continue the exchange of data in a secure manner even in case of packet losses, by accepting a reduced efficiency with respect to the I-CSA protocol.