48 citations · 102 across the 19 of their papers we have counts for
31 papers
Deferred Objects to Enhance Smart Contract Programming with Optimistic Parallel Execution
George Mitenkov, Igor Kabiljo, Zekun Li +6
One of the main bottlenecks of blockchains is smart contract execution. To increase throughput, modern blockchains try to execute transactions in parallel. Unfortunately, however,…
Shoal: Improving DAG-BFT Latency And Robustness
Alexander Spiegelman, Balaji Arun, Rati Gelashvili +1
The Narwhal system is a state-of-the-art Byzantine fault-tolerant scalable architecture that involves constructing a directed acyclic graph (DAG) of messages among a set of validat…
Bullshark: The Partially Synchronous Version
Alexander Spiegelman, Neil Giridharan, Alberto Sonnino +1
The purpose of this manuscript is to describe the deterministic partially synchronous version of Bullshark in a simple and clean way. This result is published in CCS 2022, however,…
Block-STM: Scaling Blockchain Execution by Turning Ordering Curse to a Performance Blessing
Rati Gelashvili, Alexander Spiegelman, Zhuolun Xiang +5
Block-STM is a parallel execution engine for smart contracts, built around the principles of Software Transactional Memory. Transactions are grouped in blocks, and every execution…
Make Every Word Count: Adaptive BA with Fewer Words
Shir Cohen, Idit Keidar, Alexander Spiegelman
Byzantine Agreement is a key component in many distributed systems. While Dolev and Reischuk have proven a long time ago that quadratic communication complexity is necessary for wo…
Bullshark: DAG BFT Protocols Made Practical
Alexander Spiegelman, Neil Giridharan, Alberto Sonnino +1
We present Bullshark, the first directed acyclic graph (DAG) based asynchronous Byzantine Atomic Broadcast protocol that is optimized for the common synchronous case. Like previous…
Be Aware of Your Leaders
Shir Cohen, Rati Gelashvili, Lefteris Kokoris Kogias +4
Advances in blockchains have influenced the State-Machine-Replication (SMR) world and many state-of-the-art blockchain-SMR solutions are based on two pillars: Chaining and Leader-r…
Jolteon and Ditto: Network-Adaptive Efficient Consensus with Asynchronous Fallback
Rati Gelashvili, Lefteris Kokoris-Kogias, Alberto Sonnino +2
Existing committee-based Byzantine state machine replication (SMR) protocols, typically deployed in production blockchains, face a clear trade-off: (1) they either achieve linear c…
Narwhal and Tusk: A DAG-based Mempool and Efficient BFT Consensus
George Danezis, Eleftherios Kokoris Kogias, Alberto Sonnino +1
We propose separating the task of reliable transaction dissemination from transaction ordering, to enable high-performance Byzantine fault-tolerant quorum-based consensus. We desig…
Be Prepared When Network Goes Bad: An Asynchronous View-Change Protocol
Rati Gelashvili, Lefteris Kokoris-Kogias, Alexander Spiegelman +1
The popularity of permissioned blockchain systems demands BFT SMR protocols that are efficient under good network conditions (synchrony) and robust under bad network conditions (as…
All You Need is DAG
Idit Keidar, Eleftherios Kokoris-Kogias, Oded Naor +1
We present DAG-Rider, the first asynchronous Byzantine Atomic Broadcast protocol that achieves optimal resilience, optimal amortized communication complexity, and optimal time comp…
Probabilistic Indistinguishability and the Quality of Validity in Byzantine Agreement
Guy Goren, Yoram Moses, Alexander Spiegelman
Lower bounds and impossibility results in distributed computing are both intellectually challenging and practically important. Hundreds if not thousands of proofs appear in the lit…
In Search for an Optimal Authenticated Byzantine Agreement
Alexander Spiegelman
In this paper, we challenge the conventional approach of state machine replication systems to design deterministic agreement protocols in the eventually synchronous communication m…
Not a COINcidence: Sub-Quadratic Asynchronous Byzantine Agreement WHP
Shir Cohen, Idit Keidar, Alexander Spiegelman
King and Saia were the first to break the quadratic word complexity bound for Byzantine Agreement in synchronous systems against an adaptive adversary, and Algorand broke this boun…
Using Nesting to Push the Limits of Transactional Data Structure Libraries
Gal Assa, Hagar Meir, Guy Golan-Gueta +2
Transactional data structure libraries (TDSL) combine the ease-of-programming of transactions with the high performance and scalability of custom-tailored concurrent data structure…
ACE: Abstract Consensus Encapsulation for Liveness Boosting of State Machine Replication
Alexander Spiegelman, Arik Rinberg
With the emergence of cross-organization attack-prone byzantine fault-tolerant (BFT) systems, so-called Blockchains, providing asynchronous state machine replication (SMR) solution…
Tuning PoW with Hybrid Expenditure
Itay Tsabary, Alexander Spiegelman, Ittay Eyal
Proof of Work (PoW) is a Sybil-deterrence security mechanism. It introduces an external cost to a system by requiring computational effort to perform actions. However, since its in…
Cogsworth: Byzantine View Synchronization
Oded Naor, Mathieu Baudet, Dahlia Malkhi +1
Most methods for Byzantine fault tolerance (BFT) in the partial synchrony setting divide the local state of the nodes into views, and the transition from one view to the next dicta…
FairLedger: A Fair Blockchain Protocol for Financial Institutions
Kfir Lev-Ari, Alexander Spiegelman, Idit Keidar +1
Financial institutions are currently looking into technologies for permissioned blockchains. A major effort in this direction is Hyperledger, an open source project hosted by the L…
Mind the Mining
Guy Goren, Alexander Spiegelman
In this paper we revisit the mining strategies in proof of work based cryptocurrencies and propose two strategies, we call smart and smarter mining, that in many cases strictly dom…
Fast Concurrent Data Sketches
Arik Rinberg, Alexander Spiegelman, Edward Bortnikov +4
Data sketches are approximate succinct summaries of long streams. They are widely used for processing massive amounts of data and answering statistical queries about it in real-tim…
Validated Asynchronous Byzantine Agreement with Optimal Resilience and Asymptotically Optimal Time and Word Communication
Ittai Abraham, Dahlia Malkhi, Alexander Spiegelman
We provide a new protocol for Validated Asynchronous Byzantine Agreement. Validated (multi-valued) Asynchronous Byzantine Agreement is a key building block in constructing Atomic B…
Game of Coins
Alexander Spiegelman, Idit Keidar, Moshe Tennenholtz
We formalize the current practice of strategic mining in multi-cryptocurrency markets as a game, and prove that any better-response learning in such games converges to equilibrium.…
Integrated Bounds for Disintegrated Storage
Alon Berger, Idit Keidar, Alexander Spiegelman
We point out a somewhat surprising similarity between non-authenticated Byzantine storage, coded storage, and certain emulations of shared registers from smaller ones. A common cha…