Quantum Shared Broadcasting

Truman Welling, Rémi A. Chou, Aylin Yener

This work considers a secret sharing problem where the dealer uses a classical-quantum channel to divide and distribute shares to two users by encoding the secret so that the channel observation of each user is their share. The channel observations of a single user contains very little information about the secret, but the two users together can recover the secret. We derive a one-shot and an asymptotic achievability result for secret sharing over a quantum broadcast channel. Additionally, our achievability results coincide with the secret sharing capacity for the classical broadcast channel.

Ri‐Gui Zhou, Xiaoxue Zhang, Lin-Tao Du

Timothy C. Ralph, Thomas Symul, Ping Koy Lam +3 more

Jian Wang, Quan Zhang, Chaojing Tang

Broadcast encryption allows the sender to securely distribute his/her secret to a dynamically changing group of users over a broadcast channel. In this paper, we just take account of a simple broadcast communication task in quantum scenario, in which the central party broadcasts his secret to multi-receiver via quantum channel. We present three quantum broadcast communication schemes. The first scheme utilizes entanglement swapping and Greenberger–Horne–Zeilinger state to fulfil a task that the central party broadcasts the secret to a group of receivers who share a group key with him. In the second scheme, based on dense coding, the central party broadcasts the secret to multi-receiver, each of which shares an authentication key with him. The third scheme is a quantum broadcast communication scheme with quantum encryption, in which the central party can broadcast the secret to any subset of the legal receivers.

Juan A. Garay, Clint Givens, Rafail Ostrovsky +1 more

Verifiable secret sharing (VSS) is a fundamental cryptographic primitive, lying at the core of secure multi-party computation (MPC) and, as the distributed analogue of a commitment functionality, used in numerous applications. In this paper we focus on unconditionally secure VSS protocols with honest majority. In this setting it is typically assumed that parties are connected pairwise by authenticated, private channels, and that in addition they have access to a “broadcast ” channel. Because broadcast cannot be simulated on a point-to-point network when a third or more of the parties are corrupt, it is impossible to construct VSS (and more generally, MPC) protocols in this setting without using a broadcast channel (or some equivalent addition to the model). A great deal of research has focused on increasing the efficiency of VSS, primarily in terms of round complexity. In this work we consider a refinement of the round complexity of VSS, by adding a measure we term broadcast complexity. We view the broadcast channel as an expensive resource and seek to minimize the number of rounds in which it is invoked as well. We construct a (linear) VSS protocol which uses the broadcast channel only twice in the sharing phase, while running in an overall constant number of rounds. 1

Shunlong Luo