Ran Cohen

Principal Research Scientist

Email: rancohen@ccs.neu.edu

I am a principal research scientist at the Khoury College of Computer Sciences at Northeastern University.

Prior to that, I spent two great 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.
I completed my Ph.D. in 2016 working at the Cryptography Research Group at Bar-Ilan University, where I was very fortunate to have Yehuda Lindell as my advisor.
I received my M.Sc. from the Department of Mathematics at Bar-Ilan University under the supervision of Boris Kunyavskii.

My research interests are in cryptography and distributed computing, with a focus on secure multiparty computation and consensus protocols.

Cyptography Online Talks

Due to the global COVID-19 outbreak, many conferences and seminars are carried out as online events.
Information about online talks on Cryptograpy (and more) can be found here.

Program Committees

CANS 2020 - The 18th International Conference on Cryptology and Network Security
PODC 2020 - The 39th ACM Symposium on Principles of Distributed Computing
EUROCRYPT 2020 - The 39th Annual International Conference on the Theory and Applications of Cryptographic Techniques
TCC 2019 - The 17th Theory of Cryptography Conference

Publications

(see dblp and Google scholar)

Multiparty Generation of an RSA Modulus
Megan Chen, Ran Cohen, Jack Doerner, Yashvanth Kondi, Eysa Lee, Schuyler Rosefield, and abhi shelat
- Manuscript 2020
- Preliminary full version [eprint]

Succinctly Reconstructed Distributed Signatures and Balanced Byzantine Agreement
Elette Boyle, Ran Cohen, and Aarushi Goel
- Manuscript 2020
- Preliminary full version [eprint] [arxiv]

Broadcast-Optimal Two-Round MPC
Ran Cohen, Juan Garay, and Vassilis Zikas
- Advances in Cryptology - EUROCRYPT 2020 (to appear)
- Preliminary full version [eprint]

Is Information-Theoretic Topology-Hiding Computation Possible?
Marshall Ball, Elette Boyle, Ran Cohen, Tal Malkin, and Tal Moran
- Theory of Cryptography Conference - TCC 2019 [link]
- Preliminary full version [eprint]

On the Round Complexity of Randomized Byzantine Agreement
Ran Cohen, Iftach Haitner, Nikolaos Makriyannis, Matan Orland, and Alex Samorodnitsky
- International Symposium on Distributed Computing - DISC 2019 [link]
- Preliminary full version [eprint] [arxiv]
- [slides] (by Nikos)

Adaptively Secure MPC with Sublinear Communication Complexity
Ran Cohen, abhi shelat, and Daniel Wichs
- Advances in Cryptology - CRYPTO 2019 [link]
- Preliminary full version [eprint]
- [slides] [video] (by abhi)

Must the Communication Graph of MPC Protocols be an Expander?
Elette Boyle, Ran Cohen, Deepesh Data, and Pavel Hubacek
- Advances in Cryptology - CRYPTO 2018 [link]
- Preliminary full version [eprint]
- [slides] [video]

From Fairness to Full Security in Multiparty Computation
Ran Cohen, Iftach Haitner, Eran Omri, and Lior Rotem
- Security and Cryptography for Networks - SCN 2018 [link]
- Preliminary full version [eprint]
- [slides]

Round-Preserving Parallel Composition of Probabilistic-Termination Cryptographic Protocols
Ran Cohen, Sandro Coretti, Juan Garay, and Vassilis Zikas
- International Colloquium on Automata, Languages, and Programming - ICALP 2017 [link]
- Preliminary full version [eprint]
- [slides]

Probabilistic Termination and Composability of Cryptographic Protocols
Ran Cohen, Sandro Coretti, Juan Garay, and Vassilis Zikas
- Journal of Cryptology, 2019 [link]
- Advances in Cryptology - CRYPTO 2016 [link]
- Full version [eprint]
- [slides] [video]

Asynchronous Secure Multiparty Computation in Constant Time
Ran Cohen
- Public-Key Cryptography - PKC 2016 [link]
- Preliminary full version [eprint]
- [slides]

Characterization of Secure Multiparty Computation Without Broadcast
Ran Cohen, Iftach Haitner, Eran Omri, and Lior Rotem
- Journal of Cryptology, 2018 [link]
- Theory of Cryptography Conference - TCC 2016-A [link]
- Full version [eprint]
- [slides] [video]

On Adaptively Secure Multiparty Computation with a Short CRS
Ran Cohen and Chris Peikert
- Security and Cryptography for Networks - SCN 2016 [link]
- Preliminary full version [eprint]
- [slides]

Fairness versus Guaranteed Output Delivery in Secure Multiparty Computation
Ran Cohen and Yehuda Lindell
- Journal of Cryptology, 2017 [link]
- Advances in Cryptology - ASIACRYPT 2014 [link]
- Full version [eprint]
- [slides]

Group Law Algorithms for Jacobian Varieties of Curves over Finite Fields
Ran Cohen
- Algebraic Geometry and Its Applications, volume 5 of Number Theory and its Applications, 2008 [link]
- Preliminary full version [PDF]

Ph.D. Thesis

Studies on Full Security in Multiparty Computation
Ran Cohen
- Ph.D. Dissertation, Bar-Ilan University, 2017 [PDF]

Teaching

Seminar on Secure Multi-Party Computation (with Iftach Haitner), Tel Aviv University, 2017, [link]
Discrete Mathematics, Bar-Ilan University, 2011-2016 (teaching assistant)
Volunteered at the program for talented youth in mathematics, Bar-Ilan University, 2015