Publications associées à Réseau bitcoin

Breaking Blockchain Rationality with Out-of-Band Collusion

Bryan Alexander Ford, Verónica del Carmen Estrada Galiñanes, Louis-Henri Manuel Jakob Merino, Haoqian Zhang, Mahsa Bastankhah

Blockchain systems often rely on rationality assumptions for their security, expecting that nodes are motivated to maximize their profits. These systems thus design their protocols to incentivize nodes to execute the honest protocol but fail to consider ou ...

Springer International Publishing Ag2024

Building Strongly-Consistent Systems Resilient to Failures, Partitions, and Slowdowns

Cristina Basescu

Distributed systems designers typically strive to improve performance and preserve availability despite failures or attacks; but, when strong consistency is also needed, they encounter fundamental limitations. The bottleneck is in replica coordination, whi ...

EPFL2023

Byzantine consensus is Θ(n^2): the Dolev-Reischuk bound is tight even in partial synchrony!

Rachid Guerraoui, Jovan Komatovic, Manuel José Ribeiro Vidigueira, Pierre Philippe Civit, Vincent Gramoli, Seth Gilbert

The Dolev-Reischuk bound says that any deterministic Byzantine consensus protocol has (at least) quadratic (in the number of processes) communication complexity in the worst case: given a system with n processes and at most f < n/3 failures, any solution t ...

2023

Flash Freezing Flash Boys: Countering Blockchain Front-Running

Bryan Alexander Ford, Verónica del Carmen Estrada Galiñanes, Louis-Henri Manuel Jakob Merino, Haoqian Zhang

Front-running, the practice of benefiting from advanced knowledge of pending transactions, has proliferated in the cryptocurrency space with the emergence of decentralized finance. Front-running causes devastating losses to honest participants-estimated at ...

IEEE2022

Toward Mobile Distributed Ledgers

Boi Faltings, Sujit Prakash Gujar, Dimitrios Chatzopoulos, Anurag Jain

Advances in mobile computing have paved the way for new types of distributed applications that can be executed solely by mobile devices on Device-to-Device (D2D) ecosystems (e.g., crowdsensing). Sophisticated applications, like cryptocurrencies, need distr ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2022

Byzantine Consensus is Θ(n^2): The Dolev-Reischuk Bound is Tight even in Partial Synchrony!

Rachid Guerraoui, Jovan Komatovic, Vincent Gramoli, Pierre Philippe Civit, Seth Gilbert, Manuel José Ribeiro Vidigueira

The Dolev-Reischuk bound says that any deterministic Byzantine consensus protocol has (at least) quadratic communication complexity in the worst case. While it has been shown that the bound is tight in synchronous environments, it is still unknown whether ...

Dagstuhl Publishing2022

Asynchronous distributed coordination and consensus with threshold logical clocks

Bryan Alexander Ford

Consensus protocols for asynchronous networks are usually complex and inefficient, leading practical systems to rely on synchronous protocols. The invention proposes an approach to simplify asynchronous consensus by building it atop a novel threshold logic ...

2021

CALYPSO: Private Data Management for Decentralized Ledgers

Bryan Alexander Ford, Linus Gasser, Eleftherios Kokoris Kogias, Philipp Svetolik Jovanovic, Enis Ceyhun Alp

Distributed ledgers provide high availability and integrity, making them a key enabler for practical and secure computation of distributed workloads among mutually distrustful parties. Many practical applications also require strong confidentiality, howeve ...

2021

A Standalone FPGA-Based Miner for Lyra2REv2 Cryptocurrencies

Alexios Konstantinos Balatsoukas Stimming, Pascal Giard, Michiel Van Beirendonck

Lyra2REv2 is a hashing algorithm that consists of a chain of individual hashing algorithms, and it is used as a proof-of-work function in several cryptocurrencies. The most crucial and exotic hashing algorithm in the Lyra2REv2 chain is a specific instance ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2020

Quantifying Endogeneity of Cryptocurrency Markets

Thomas Alois Weber, Michael Mark

We construct a ‘reflexivity’ index to measure the activity generated endogenously within a market for cryptocurrencies. For this purpose, we fit a univariate self-exciting Hawkes process with two classes of parametric kernels to high-frequency trading data ...

2022

Time in cryptography

Gwangbae Choi

Time travel has always been a fascinating topic in literature and physics. In cryptography, one may wonder how to keep data confidential for some time. In this dissertation, we will study how to make private information travel to the future. This dissertat ...

EPFL2020

Online Payments by Merely Broadcasting Messages

Rachid Guerraoui, Jovan Komatovic, Dragos-Adrian Seredinschi, Matej Pavlovic, Daniel Patrick Collins, Matteo Monti, Athanasios Xygkis, Andrei Tonkikh

We address the problem of online payments, where users can transfer funds among themselves. We introduce Astro, a system solving this problem efficiently in a decentralized, deterministic, and completely asynchronous manner. Astro builds on the insight tha ...

IEEE2020

Secure, Confidential Blockchains Providing High Throughput and Low Latency

Eleftherios Kokoris Kogias

One of the core promises of blockchain technology is that of enabling trustworthy data dissemination in a trustless environment. What current blockchain systems deliver, however, is slow dissemination of public data, rendering blockchain technology unusabl ...

EPFL2019

A Blockchain Consensus Protocol With Horizontal Scalability

Kelong Cong

Blockchain technology has the potential to decentralise many traditionally centralised systems. However, scalability remains a key challenge. A horizontally scalable solution, where performance increases by adding more nodes, would move blockchain systems ...

IEEE2018

Enhancing Bitcoin Security and Performance with Strong Consistency via Collective Signing

Bryan Alexander Ford, Linus Gasser, Philipp Svetolik Jovanovic, Nicolas Gailly, Ismail Khoffi

While showing great promise, Bitcoin requires users to wait tens of minutes for transactions to commit, and even then, offering only probabilistic guarantees. This paper introduces ByzCoin, a novel Byzantine consensus protocol that leverages scalable colle ...

USENIX Association2016

Poster: LocalCoin: An Ad-hoc Payment Scheme for Areas with High Connectivity

Boi Faltings, Sujit Prakash Gujar, Dimitrios Chatzopoulos

The popularity of digital currencies, especially cryptocurrencies, has been continuously growing since the appearance of Bitcoin. Bitcoin is a peer-to-peer (P2P) cryptocurrency protocol enabling transactions between individuals without the need of a truste ...

Assoc Computing Machinery2016

Abstractions for Solving Consensus and Related Problems with Byzantine Faults

Zarko Milosevic

We become increasingly dependent on online services; therefore, their availability and correct behavior become increasingly important. Software replication is a popular technique for ensuring that computer systems continue to provide a correct service even ...

EPFL2013

Scalable and Secure Polling in Dynamic Distributed Networks

Rachid Guerraoui, Anne-Marie Kermarrec, Hamza Harkous, Florian Huc

We consider the problem of securely conducting a poll in synchronous dynamic networks equipped with a Public Key Infrastructure (PKI). Whereas previous distributed solutions had a communication cost of O(n^2) in an n nodes system, we present SPP (Secure an ...

2012