Byzantine Agreement with HomonymsByzantine Agreement • February 24th, 2024
Proposition 28 (Unforgeability) If α correct processes with identifier i perform Broadcast(i, m, r) in superround r and some correct process performs Accept(i, α′, m, r) in superround r then r ≤ r and 0 ≤ α ≤ α + fi.
Byzantine AgreementByzantine Agreement • November 15th, 2017
In order to make flying safer, researchers studied possible failures of various sensors and machines used in airplanes. While trying to model the failures, they were confronted with the following problem: Failing machines did not just crash, instead they sometimes showed arbitrary behavior before stopping com- pletely. With these insights researchers modeled failures as arbitrary failures, not restricted to any patterns.
ContractByzantine Agreement • March 6th, 2024
Load balanced Scalable Byzantine Agreement through Quorum Building, with Full InformationByzantine Agreement • December 16th, 2020
val@uvic.ca, {sdlonergan, amitabh.trehaan}@gmail.com, Department of Computer Science, University of New Mexico, Albuquerque, NM
Player-Centric Byzantine AgreementByzantine Agreement • November 18th, 2011
Abstract. Most of the existing feasibility results on Byzantine Agreement (BA) are of an all-or-nothing fashion: in Broadcast they address the question whether or not there exists a protocol which allows any player to broadcast his input. Similarly, in Consensus the question is whether or not consensus can be reached which respects pre-agreement on the inputs of all correct players. In this work, we introduce the natural notion of player-centric BA which is a class of BA prim- itives, denoted as PCBA = PCBA( ) C⊆P , parametrized by subsets of the player set. For each primitive PCBA( ) PCBA the validity is defined on the input(s) of the players in . Broadcast (with sender p) and Consensus are special (extreme) cases of PCBA primitives for = p and = , respectively.
Byzantine Agreement, Made TrivialByzantine Agreement • March 19th, 2018
We present a very simple, cryptographic, Byzantine-agreement protocol that, with n = 3t + 1 players, t of which are malicious, halts in expected 9 rounds.
Byzantine Agreement with Homonyms (Accord Byzantin avec des Homonymes)Byzantine Agreement • April 24th, 2012
Carole Delporte-Gallet, Hugues Fauconnier, Rachid Guerraoui, Anne-Marie Kermarrec, Eric Ruppert, et al.. Byzantine Agreement with Homonyms (Accord Byzantin avec des Homonymes). 2012. hal- 00689119
Byzantine Agreement Using AuthenticationByzantine Agreement • November 19th, 2009
Round-Optimal Byzantine AgreementByzantine Agreement • June 2nd, 2022
The Byzantine Agreement – part 2Byzantine Agreement • October 18th, 2017
• If the processes start with different initial values, then the final decision could be any of these (as long as it is consistent)
Required: Agreement, Termination, ValidityByzantine Agreement • June 5th, 2022
Player-Centric Byzantine AgreementByzantine Agreement • May 27th, 2010
Validity in Network-Agnostic Byzantine AgreementByzantine Agreement • October 28th, 2024
In Byzantine Agreement (BA), there is a set of n parties, from which up to t can act byzantine. All honest parties must eventually decide on a common value (agreement), which must belong to a set determined by the inputs (validity). Depending on the use case, this set can grow or shrink, leading to various possible desiderata collectively known as validity conditions. Varying the validity property requirement can affect the regime under which BA is solvable. We study how the selected validity property impacts BA solvability in the network-agnostic model, where the network can either be synchronous with up to ts byzantine parties or asynchronous with up to ta ts byzantine parties.
Jerusalem, IsraelByzantine Agreement • November 19th, 2007
This constitutes significant progress over the best known randomized BA protocol in the same setting which has a round-complexity of Θ( t ) rounds [9], and answers an open problem
On Byzantine Agreement over (2, 3)-Uniform HypergraphsByzantine Agreement • December 15th, 2004
Byzantine AgreementByzantine Agreement • June 25th, 2007
At the next round all players measure all the pieces they have; a leader is selected according to the shared minimum; and the corresponding measured bit serves as the “global coin”.
Federated Byzantine Agreement to Ensure Trustworthiness of Digital Manufacturing PlatformsByzantine Agreement • May 5th, 2018
In this paper, we explore the use of the Stellar Consensus Protocol (SCP) and its Federated Byzantine Agreement (FBA) algorithm for ensuring trust and reputation between federated, cloud-based platform instances (nodes) and their participants. Our approach is grounded on federated consensus mechanisms, which promise data quality managed through computational trust and data replication, without a centralized authority. We perform our experimentation on the ground of the NIMBLE cloud manufacturing platform, which is designed to support growth of B2B digital manufacturing communities and their businesses through federated platform services, managed by peer-to-peer networks. We discuss the message exchange flow between the NIMBLE application logic and Stellar consensus logic.
The Byzantine Agreement – part 2Byzantine Agreement • October 18th, 2017
Byzantine Agreement on Steroids Silvio MicaliByzantine Agreement • March 27th, 2017
Abstract. As insightfully defined by Pease, Shostak, and Lamport, Byzantine agreement (BA) has rightfully received enormous attention, and is one of the most demanding and compelling notions in fault-tolerant and secure computation. Yet, BA protocols are too slow for most practical applications, and often satisfy conditions much weaker than those originally envisaged.
Byzantine Agreement: Optimistic AnalysisByzantine Agreement • May 23rd, 2019
Byzantine Agreement & Fault Diagnosis Agreement in Dynamic Ad-Hoc EnvironmentByzantine Agreement • April 18th, 2008
Since wireless communication and mobile computing are becoming more and more ubiquitous, the reliability and fault tolerance of the Mobile Ad-hoc Network (MANET) has become an important topic. In order to provide a reliable environment, a mechanism that allows a set of nodes to reach a common agreement, even in the presence of faulty nodes, is needed. Therefore, the Byzantine Agreement (BA) problem has drawn attention of more researchers. Traditionally, the BA problem was focused on wired networks. We know that the physical topology of a wired network is static, but the physical topology of an MANET is dynamic. Thus, previous BA protocols are not applicable in an MANET. In this paper, a new protocol is proposed to solve the BA problem with malicious faulty components in dynamic MANET. Furthermore, we also propose a new Fault Diagnosis Agreement (FDA) protocol to detect/locate faulty components to provide a highly reliable environment. From the performance perspective, the proposed prot
Byzantine AgreementByzantine Agreement • May 28th, 2022
Byzantine Agreement Service for Cooperative Wireless Embedded SystemsByzantine Agreement • May 8th, 2017
This paper presents a framework for Byzantine fault tolerant agreement for small-sized groups of autonomous, wirelessly con- nected systems. It focuses, besides providing support for general purpose value agreement, on the agreement of distributed sensor readings. The latter enables to establish a joint view on context conditions, thereby building the basis for joint coordinated actions. As classical Byzantine fault tolerant agreement protocols require 3t + 1 participants to tolerate t faulty nodes, we also consider a hybrid fault model by utilizing a trusted subsystem, which can only be subject to crashes. The latter reduces the required group size for agreement to 2t + 1 nodes and reduces the message complexity of the protocol, which is essential for the targeted scenarios. The experiment results show that the trusted subsystem can effectively increase the efficiency. 1
Byzantine Agreement: ApplicationsByzantine Agreement • April 12th, 2007
Byzantine Agreement with a Rational AdversaryByzantine Agreement • July 9th, 2012
Abstract. Traditionally, cryptographers assume a “worst-case” adver- sary who can act arbitrarily. More recently, they have begun to consider rational adversaries who can be expected to act in a utility-maximizing way. Here we apply this model for the first time to the problem of Byzan- tine agreement (BA) and the closely related problem of broadcast, for natural classes of utilities. Surprisingly, we show that many known re- sults (e.g., equivalence of these problems, or the impossibility of toler- ating t ≥ n/2 corruptions) do not hold in the rational model. We study the feasibility of information-theoretic (both perfect and statistical) BA assuming complete or partial knowledge of the adversary’s preferences. We show that perfectly secure BA is possible for t < n corruptions given complete knowledge of the adversary’s preferences, and charac- terize when statistical security is possible with only partial knowledge. Our protocols have the added advantage of being more efficient than
Byzantine Agreement with Optimal Resilience via Statistical Fraud DetectionByzantine Agreement • June 30th, 2022
Proof. Consider the sequence (At)t∈[T ], where A0 = 0, At = At−1 + ΣG(t)2 − 1 ǫ2mf. By Lemma 8, E[ΣG(t)2] ≥ 1 ǫ2mf, so (At)t is a submartingale. Since ΣG(t) is a sum of at most mn coin flips, |At − At−1| = ΣG√(t)2 ≤ mn · c ln n with high probability. By Azuma’s inequality, with high probability, AT ≥
Byzantine Agreement with Faulty Majority using Bounded BroadcastByzantine Agreement • October 29th, 2018
Byzantine Agreement introduced in [Pease, Shostak, Lamport, 80] is a widely used building block of reliable distributed protocols. It sim- ulates broadcast despite the presence of faulty parties within the network, traditionally using only private unicast links. Under such condi- tions, Byzantine Agreement requires more than 2/3 of the parties to be compliant. [Fitzi, Mau- rer, 00], constructed a Byzantine Agreement pro- tocol for any compliant majority based on an ad- ditional primitive allowing transmission to any two parties simultaneously. They proposed a problem of generalizing these results to wider channels and fewer compliant parties. We prove that 2f < kh condition is necessary and suffi- cient for implementing broadcast with h compli- ant and f faulty parties using k-cast channels.
Byzantine Agreement with Dual Failure Mode forByzantine Agreement • December 18th, 2006
In a distributed system, the task must achieve an agreement; a Mobile Ad-hoc NETwork (MANET) is trending towards distributed systems that support for mobile computing. The Byzantine Agreement (BA) protocols designed in traditional networks do not perform well in MANET environment. There are several properties in MANET such that MANET can provide processor join to the network or leave anytime with non-infrastructure. A group of multiple processors in MANET is cooperating to achieve some objectives. In order to move up the capability of the faulty tolerance and ensure network security, provide stable distributed system environment, a protocol VSAP (Virtual Subnet Agreement Protocol) to solve the BA problem with malicious and dormant faults (dual failure mode) is proposed. VSAP uses the minimum number of message exchange rounds to make all correct processors agree on a common value and can tolerate the maximum number of allowable faulty components. The proposed protocol is not only solvin
Byzantine agreementByzantine Agreement • January 27th, 2024
Figure 10.2: Four-process vs. eight-process execution in Byzantine agreement connectivity lower bound. Because Byzantine Cˇ can simulate C0, D1, B1, A1, and C1, good processes A0, B0 and D0 must all decide 0 or risk violating validity.
Byzantine AgreementByzantine Agreement • November 2nd, 2018
In order to make flying safer, researchers studied possible failures of various sensors and machines used in airplanes. While trying to model the failures, they were confronted with the following problem: Failing machines did not just crash, instead they sometimes showed arbitrary behavior before stopping com- pletely. With these insights researchers modeled failures as arbitrary failures, not restricted to any patterns.
Byzantine Agreement: From Theory to PracticeByzantine Agreement • May 23rd, 2019
Byzantine Agreement with Bounded BroadcastByzantine Agreement • April 7th, 2008
Byzantine Agreement introduced in [Pease, Shostak, Lamport, 80] is a widely used building block of reliable distributed protocols. It sim- ulates broadcast despite the presence of faulty parties within the network, traditionally using only private unicast links. Under such condi- tions, Byzantine Agreement requires more than 2/3 of the parties to be honest. [Fitzi, Maurer, 00], constructed a Byzantine Agreement protocol for any honest majority based on an additional primitive allowing transmission to any two par- ties simultaneously. We generalize these results using a primitive allowing transmission among any fixed number of parties simultaneously, and prove that a 2k party channel is necessary and sufficient for implementing broadcast when hon- est parties are in 1/k minority.
The Byzantine Agreement Protocol Applied to SecurityByzantine Agreement • January 12th, 2005
This system makes use of solutions to the Byzantine General's Problem, developed earlier by Lamport and others. Byzantine Agreement Protocols will be used to achieve consensus about which nodes have been compromised or failed, with a series of synchronized, secure rounds of message exchanges. Once a consensus has been reached, the offending nodes can be isolated and countermeasure actions can be initiated by the system.
Byzantine AgreementByzantine Agreement • June 29th, 2012
Accurate Byzantine Agreement with FeedbackByzantine Agreement • May 5th, 2020
The standard Byzantine Agreement (BA) problem requires non-faulty processes to agree on a common value. In many real-world applications, it is important that the processes agree on the correct value rather than any value. In this paper, we present a problem called Accurate Byzantine Agreement (ABA) in which all processes get a common feedback (or payoff) from the environment indicating if the value they agreed upon was correct or not. The solution to this problem, referred to as the ABA algorithm, requires the non-faulty processes to incorporate the feedback so that their chance of choosing the correct value improves over subsequent iterations of the algorithm. We present an algorithm that solves the ABA problem based on two key ingre- dients: a standard solution to the BA problem and a multiplicative method to maintain and update process weights indicative of how often they are correct. We give guarantees on the accuracy of the algorithm based on assumptions on the accuracy of the pro
