MPC with Synchronous Security and Asynchronous Responsiveness

Original paper: MPC with Synchronous Security and Asynchronous Responsiveness. Chen-Da Liu-Zhang, Julian Loss, Ueli Maurer, Tal Moran, and Daniel Tschudi. 2019

Summary

  • Synchronous protocols have higher corruption thresholds and asynchronous protocols have responsiveness.
  • Let \(T\) be the number of faults tolerated by the synchronous protocols. Let \(t\) be the number of faults under which the same synchronous protocol is responsive.
  • If the security is abort, MPC iff \(T+2t
  • If the security is full, MPC iff
    • \(T
    • \(T+2t
  • Technique: Assume black box asynchronous and synchronous MPC protocols, threshold encryption, two-threshold asynchronous protocol with full security up to \(t\) corruptions, and a synchronous protocol with security up to \(T\) corruptions. Then they provide a compiler in the new model.

References

Chen-Da Liu-Zhang, Julian Loss, Ueli Maurer, Tal Moran, and Daniel Tschudi. 2019. “MPC with Synchronous Security and Asynchronous Responsiveness.” https://eprint.iacr.org/2019/159.