Prof. Niv Gilboa

We present information-theoretically secure schemes for sharing and modifying secrets among a dynamic swarm of computing devices. The schemes support an unlimited number of changes to the swarm including players joining and leaving the swarm, while swarms may be merged, cloned or split. The schemes securely and distributively maintain a global state for the swarm, and support an unlimited number of changes to the state according to received input. Our schemes are based on a novel construction of a strongly oblivious universal TuringMachine and on a distributed evaluation of this TM that reveals nothing to an adversary beyond a bound on the space complexity of the TM.