A central problem in cryptography is that of converting protocols that offer security against passive (or semi-honest) adversaries into ones that offer security against active (or malicious) adversaries. This problem has been the topic of a large body of work in the area of secure Multi-Party Computation (MPC). Despite these efforts there are still big efficiency gaps between the best protocols in these two settings. In this talk I will present a new paradigm for transforming passively secure MPC protocols into actively secure ones without effecting the communication complexity. Using this approach it is possible to close the communication complexity gap between the passive and the active cases for many natural information theoretic MPC settings. The approach is based on novel techniques for securing circuits against tampering attacks which can be of independent interest.
The talk is based on joint works with Yuval Ishai, Antigoni Polychroniadou, Manoj M. Prabhakaran, Amit Sahai and Eran Tromer.