This Week in Blockchain Research Issue #91

Issue #91

Issue #91

Paper of the Week:

Paper Title: Highway: Efficient Consensus with Flexible Finality.


  1. There has been recently a lot of progress in designing efficient partially synchronous BFT consensus protocols that are meant to serve as core consensus engines for Proof of Stake blockchain systems.

  2. While the state-of-the-art solutions attain virtually optimal performance under this theoretical model, there is still room for improvement, as several practical aspects of such systems are not captured by this model.

  3. Most notably, during regular execution, due to financial incentives in such systems, one expects an overwhelming fraction of nodes to honestly follow the protocol rules and only few of them to be faulty, most likely due to temporary network issues.

  4. Intuitively, the fact that almost all nodes behave honestly should result in stronger confidence in blocks finalized in such periods, however it is not the case under the classical model, where finality is binary.

  5. This work proposes a new consensus protocol that is safe and live in the classical partially synchronous BFT model, while at the same time offering practical improvements over existing solutions.

  6. Specifically, block finality is not binary but is expressed by fraction of nodes that would need to break the protocol rules in order for a block to be reverted.

  7. During periods of honest participation finality of blocks might reach well beyond 1∕3 (as what would be the maximum for classical protocols), up to even 1 (complete certainty).

  8. Having finality defined this way, this work offers flexibility with respect to the configuration of security thresholds among nodes running the protocol, allowing nodes with lower thresholds to reach finality faster than the ones requiring higher levels of confidence.

AuthorsDaniel Kane*, Andreas Fackler†, Adam Gągol‡, Damian Straszak‡, and Vlad Zamfir§,

Affiliations: * UC San Diego, † CasperLabs LLC, ‡ Cardinal Cryptography, and § Ethereum Research.


1. Paper Title: Blockchain for steganography: advantages, new algorithms and open challenges.

Summary: The advantages of blockchain in steganography, which include the ability to embed hidden data without manual change in the original data, as well as the readiness of the blockchain platform for data transmission and storage, which eliminates the need for the Steganographer to design and implement a new platform for data transmission and storage.

Authors: Omid Torki*, Maede Ashouri-Talouki*, and Mojtaba Mahdavi*,

Affiliations* University of Isfahan.

2. Paper Title: Eth2Vec: Learning Contract-Wide Code Representations for Vulnerability Detection on Ethereum Smart Contracts.

Summary: A machine-learning-based static analysis tool for vulnerability detection, with robustness against code rewrites in smart contracts.

Authors: Nami Ashizawa*, Naoto Yanai*, Jason Paul Cruz*, and Shingo Okamura†,

Affiliations* Osaka University and † National Institute of Technology, Nara College.

3. Paper Title: What is Meant by Permissionless Blockchains?

Summary: This work raises the question whether current definitions of “permissionless” are adequate and come to the conclusion that several aspects either fall short in their intended meaning, or do not capture vital elements.

Authors: Nicholas Stifter*†, Aljosha Judmayer*†, Philipp Schindler*†, Andreas Kern†, and Walid Fdhila*,

Affiliations* SBA Research and † University of Vienna.


No papers.


1. Paper Title: Demand-aware Channel Topologies for Off-chain Blockchain Payments.

Summary: This work studies the impact of topologies on the performance of off-chain blockchain networks and positioned that their construction should be demand-aware.

Authors: Julia Khamis* and Ori Rottenstreich*,

Affiliations* Technion.

2. Paper Title: Sketches for Blockchains.

Summary: How sketches can detect anomalies based on efficient an summary of the state or traffic.

Authors: Ori Rottenstreich*,

Affiliations* Technion.


1. Paper Title: Linear-time zero-knowledge SNARKs for R1CS.

Summary: This paper studies zero-knowledge SNARKs for NP, where the prover incurs O(N) finite field operations to prove the satisfiability of an N-sized R1CS instance.

Authors: Jonathan Lee*, Srinath Setty†, Justin Thaler‡, and Riad Wahby§,

Affiliations* Nanotronics Imaging, † Microsoft Research, ‡ Georgetown University, § Stanford University.


1. Paper Title: Strengthened Fault Tolerance in Byzantine Fault Tolerant Replication.

Summary: This work investigates strengthened fault tolerance (SFT) in Byzantine fault tolerant (BFT) state machine replication (SMR) under partial synchrony, which provides grad- ually increased resilience guarantees (like Nakamoto Consensus) during an optimistic period when the network is synchronous and the number of Byzantine faults is small.

Authors: Zhuolun Xiang*, Dahlia Malkhi*, Kartik Nayak†, and Ling Ren‡,

Affiliations* Novi, † Duke University, and ‡ University of Illinois at Urbana-Champaign.


1. Paper Title: Fiat Money, Cryptocurrencies, and the Pure Theory of Money.

Summary: This paper attempts to account for the rising value of cryptocurrencies using basic concepts of monetary theory.

AuthorsDavid Glasner*,

Affiliations: * Government of the United States of America - Bureau of Economics.

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