Description du projet
Algorithmes sans consensus pour des transferts d’actifs fiables
Le Bitcoin et d’autres protocoles qui reposent sur la blockchain mettent en œuvre un système décentralisé de transfert d’actifs. La difficulté réside dans le fait d’interdire à un participant de se livrer à des doubles dépenses. Le projet AT2, financé par l’UE, s’attache à relever ce défi. Baptisé «transferts asynchrones fiables», ce protocole asynchrone générique permet de résoudre le problème de l’émission causale sécurisée. Plus précisément, le projet s’emploie à développer une classe d’algorithmes sans consensus, dans la mesure où le consensus est inutile pour les transferts d’actifs. Le projet a montré qu’il est suffisant de résoudre un problème appelé «émission causale sécurisée» afin de garantir la confiance numérique dans tout type d’application par jetons, ce qui représente une solution bien plus simple. Ce projet a pour objectif de préparer la phase de commercialisation.
Objectif
Although Nakamoto’s original blockchain protocol has spurred significant innovation and financial interest in the last decade, its energy consumption becomes problematic. Besides, transaction latencies are prohibitively high and the system sustains a very low throughput. We have witnessed hundreds of alternative solutions in the last decade. Each seeks to reduce energy consumption, to obtain lower latency, or to improve throughput. All proposed alternatives, however, sacrifice either trustworthiness or efficiency. In retrospect, this is not surprising. All these solutions seek to solve a notoriously difficult problem: consensus. In short, the set of nodes in the network have to agree on the same position of a block in the chain, despite the possibility of malicious behaviour of some of the nodes, or network delays. The consensus problem has been the most studied problem in distributed computing, and many impossibility and lower bound results were established. These results translate into inherent trade-offs between trust and efficiency. In the context of our ERC AOC (Adversary-Oriented Computing) project (advanced grant), we worked on classifying distributed computing problems according to their hardness. While doing so, we revisited the issue of implementing a trustworthy payment system, i.e. the problem solved in Nakamoto’s paper. This led us to a very interesting discovery: Current blockchain protocols are tackling a problem, i.e. consensus, which is unnecessarily strong for their purpose of building a payment system. More specifically, we have shown that it is enough to solve a problem called secure causal broadcast to implement trust in any tokenized application. This is significantly simpler than consensus. We devised a generic asynchronous protocol to solve the secure causal broadcast problem, which we called AT2, Asynchronous Trustworthy Transactions, which we patented. The goal of this project is to pave the path to its commercialization.
Programme(s)
Régime de financement
ERC-POC-LS - ERC Proof of Concept Lump Sum PilotInstitution d’accueil
1015 Lausanne
Suisse