Quantum secret aggregation utilizing a network of agents

Abstract

In this work we consider the following problem: given a network of spies, all distributed in different locations in space, and assuming that each spy possesses a small, but incomplete by itself part of a big secret, is it possible to securely transmit all these partial secrets to the spymaster, so that they can be combined together in order to reveal the big secret? We refer to it as the Quantum Secret Aggregation problem, and we propose a protocol, in the form of a quantum game, with Alice taking over the role of the spymaster, that addresses this problem in complete generality. Our protocol relies on the use of maximally entangled GHZ tuples, which are symmetrically distributed among Alice and all her spies. It is the power of entanglement that makes possible the secure transmission of the small partial secrets from the agents to the spymaster. As an additional bonus, entanglement guarantees the security of the protocol, by making it statistically improbable for the notorious eavesdropper Eve to steal the big secret.