# Ran Cohen

## Principal Research Scientist

Northeastern University
Khoury College of Computer Sciences
Cybersecurity and Privacy Institute
Email: rancohen@ccs.neu.edu

### Brief Biography

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 its synergy with distributed computing, mainly focusing on secure multiparty computation and consensus protocols.

### Professional Activities

Program committee member for the following conferences:
• TCC 2020 - The 18th Theory of Cryptography Conference
• EUROCRYPT 2020 - The 39th Annual International Conference on the Theory and Applications of Cryptographic Techniques
• PODC 2020 - The 39th ACM Symposium on Principles of Distributed Computing
• CANS 2020 - The 18th International Conference on Cryptology and Network Security
• INDOCRYPT 2020 - The 21st International Conference on Cryptology in India
• TCC 2019 - The 17th Theory of Cryptography Conference
Cryptography Online Talks. Due to the global COVID-19 outbreak, many conferences and seminars are carried out as online events.
Information about online talks on Cryptography (and more) can be found here.

### Publications

• Breaking the $$O(\sqrt{n})$$-Bits Barrier: Byzantine Agreement with Polylog Bits Per-Party
Elette Boyle, Ran Cohen, and Aarushi Goel
• POCD 2021 - The 40th ACM Symposium on Principles of Distributed Computing (to appear)
• Preliminary full version [eprint] [arxiv]
• On the Power of an Honest Majority in Three-Party Computation Without Broadcast
Bar Alon, Ran Cohen, Eran Omri, and Tom Suad
• TCC 2020 - 18th Theory of Cryptography Conference [link]
• Preliminary full version [eprint]
• [slides] [video] (by Bar)
Ran Cohen, Juan Garay, and Vassilis Zikas
• EUROCRYPT 2020 - 39th Annual International Conference on the Theory and Applications of Cryptographic Techniques [link]
• Preliminary full version [eprint]
• [slides] [video]
• Adaptively Secure MPC with Sublinear Communication Complexity
Ran Cohen, abhi shelat, and Daniel Wichs
• CRYPTO 2019 - 39th Annual International Cryptology Conference [link]
• Preliminary full version [eprint]
• [slides] [video] (by abhi)
• From Fairness to Full Security in Multiparty Computation
Ran Cohen, Iftach Haitner, Eran Omri, and Lior Rotem
• SCN 2018 - 11th International Conference on Security and Cryptography for Networks [link]
• Preliminary full version [eprint]
• [slides]
• Round-Preserving Parallel Composition of Probabilistic-Termination Cryptographic Protocols
Ran Cohen, Sandro Coretti, Juan Garay, and Vassilis Zikas
• Journal of Cryptology, 2021 [link]
• ICALP 2017 - 44th International Colloquium on Automata, Languages, and Programming [link]
• Full version [eprint]
• [slides]
• Asynchronous Secure Multiparty Computation in Constant Time
Ran Cohen
• PKC 2016 - 19th International Conference on Practice and Theory in Public-Key Cryptography [link]
• Preliminary full version [eprint]
• [slides]
• Characterization of Secure Multiparty Computation Without Broadcast
Ran Cohen, Iftach Haitner, Eran Omri, and Lior Rotem
• On Adaptively Secure Multiparty Computation with a Short CRS
Ran Cohen and Chris Peikert
• SCN 2016 - 10th International Conference on Security and Cryptography for Networks [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]
• ASIACRYPT 2014 - 20th International Conference on the Theory and Application of Cryptology and Information Security [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]

### Videos

Some of my talks have been filmed and can be found online: