Partially Authenticated Algorithms for Byzantine Agreement

Byzantine agreement is a fundamental issue in fault-tolerant and secure distributed computing. Protocols solving Byzantine agreement guarantee that a sender can transmit a value to a group of receivers consistently, even if some of the nodes, including the sender, are arbitrarily faulty. In the past, protocols for Byzantine agreement were generally either authenticated or non-authenticated. Non-authenticated protocols make no use of signatures, while in authenticated protocols, all messages have to be signed. Authenticated protocols can tolerate more faults and are more message-eecient than non-authenticated protocols, but they have the disadvantage of time-consuming signature generation. In this paper, we introduce techniques to reduce the amount of signatures by combining mechanisms from authenticated and non-authenticated protocols.