Unconditional Byzantine Agreement and Multi-Party Computation Secure Against Dishonest Minorities from Scratch
Matthias Fitzi, Nicolas Gisin, Ueli M. Maurer +1 more
Abstract. It is well-known that n players, connected only by pairwise secure channels, can achieve unconditional broadcast if and only if the number t of cheaters satisfies t < n/3. In this paper, we show that this bound can be improved — at the sole price that the adversary can prevent successful completion of the protocol, but in which case all players will have agreement about this fact. Moreover, a first time slot during which the adversary forgets to cheat can be reliably detected and exploited in order to allow for future broadcasts with t < n/2. This even allows for secure multi-party computation with t < n/2 after the first detection of such a time slot.
•Jan 1, 2002•7 citations