Saar Tochner

Ph.D. candidate at The Hebrew University

Saar Tochner


I'm a Ph.D. candidate advised by Aviv Zohar at the Hebrew University of Jerusalem.

I am interested in designing and understanding different privacy and security aspects of systems, mainly in the field of cryptocurrencies.
During my research, I came across several contradictory incentives that undermine the effectiveness of the current implementation. These are fundamental trade-offs that my research aims to solve.
I have strong engineering skills, with practical experience in developing in cloud environments, implementing complex protocols with deep theory behind them, and using different technologies such as Intel SGX, developing applications on Ethereum, using zero knowledge prover systems and other cryptographic tools.

My goal is to understand incentives and build working solutions.


  • Blockchain Stretching & Squeezing: Manipulating Time For Your Best Interest [pdf] (ACM EC 22')

    Authors: Aviv Yaish*, Saar Tochner*, Aviv Zohar

    Abstract: We present a novel way for cryptocurrency miners to manipulate the effective interest-rate ▽ More

  • Twilight: A Differentially Private Payment Channel Network [pdf] (USENIX Security 22')

    Authors: Maya Dotan*, Saar Tochner*, Aviv Zohar, Yossi Gilad

    Abstract: Payment channel networks (PCNs) provide a faster and cheaper alternative to transactions ▽ More

  • SOK: Cryptocurrency Networking Context, State-of-the-Art, Challenges [pdf] (ACM Computing Surveys 21'; ARES 20')

    Authors: Maya Dotan, Yvonne-Anne Pignolet, Stefan Schmid, Saar Tochner, Aviv Zohar

    Abstract: Cryptocurrencies such as Bitcoin are realized using distributed systems and hence ▽ More

  • On Search Friction of Route Discovery in Offchain Networks [pdf] (IEEE Blockchains 20')

    Authors: Saar Tochner, Stefan Schmid

    Abstract: Offchain networks provide a promising solution to overcome the scalability challenges ▽ More

  • Proofs of Useless Work - Positive and Negative Results for Wasteless Mining Systems [pdf] (GAMES 20')

    Authors: Maya Dotan* Saar Tochner*,

    Abstract: Many blockchain systems today, including Bitcoin, rely on Proof of Work (PoW). Proof ▽ More

  • Hijacking Routes in Payment Channel Networks: A Predictability Tradeoff [pdf] (ACM AFT 20')

    Authors: Saar Tochner, Aviv Zohar, Stefan Schmid

    Abstract: Off-chain transaction networks can mitigate the scalability issues of today's trustless ▽ More

  • How to Pick Your Friends - A Game Theoretic Approach to P2P Overlay Construction [pdf] (ACM AFT 20')

    Authors: Saar Tochner, Aviv Zohar

    Abstract: A major limitation of open P2P networks is the lack of strong identities. This allows any agent ▽ More

Contact Me

A317, Benin School of Computer Science and Engineering, The Hebrew University, Giv'at Ram, Jerusalem, Israel

Phone: +972 50 205 2517