Secure multiparty computation (MPC) is one of the most impressive achievements of modern cryptography, enabling distributed computations by mutually distrusting parties in a way that guarantees privacy of the inputs and correctness of the output. Broadcast can be viewed as a specific MPC task that allows a designated sender to reliably send a message to all other parties.
Many MPC protocols consider broadcast as an atomic resource of the communication model, thus achieving optimality in terms of security guarantees, round complexity, and communication efficiency. However, broadcasting messages as an atomic operation is a strong assumption that cannot be realized in many real-life settings. Using broadcast protocols in a naive way affects the aforementioned results both in terms of feasibility and of efficiency.
In this talk I will explore secure computation over point-to-point channels, where a broadcast channel is not available, and tackle various aspects of this question: (1) how to achieve the best security guarantees, (2) how to efficiently use secure protocols as sub-routines in higher-level protocols, and (3) how to minimize the resources needed for the computation.
Ran Cohen is a principal research scientist at Northeastern University. His main areas of research are cryptography and distributed computation. Ran spent two years as a post-doctoral researcher in the Boston area, working with Shafi Goldwasser at MIT CSAIL, with abhi shelat at Northeastern University, and with Ran Canetti at Boston University, and one year at Tel Aviv
University working with Iftach Haitner. Ran received his PhD in Computer Science from Bar-Ilan University in 2016, where he was advised by Yehuda Lindell.