Secure Multi-party Quantum Computation with a Dishonest Majority

Understand

The cryptographic task of secure multi-party (classical) computation has received a lot of attention in the last decades.

• Even in the extreme case where a computation is performed between $k$ mutually distrustful players, and security is required even for the single honest player if all other players are colluding adversaries, secure protocols are known.
• For quantum computation, on the other hand, protocols allowing arbitrary dishonest majority have only been proven for $k=2$.
• In this work, we generalize the approach taken by Dupuis, Nielsen and Salvail (CRYPTO 2012) in the two-party setting to devise a secure, efficient protocol for multi-party quantum computation for any number of players $k$, and prove security against up to $k-1$ colluding adversaries.