The Pease, Shostak and Lamport study was one of the first to consider the problem of implementing coordinated behavior between processors in a distributed system in the presence of failures . Since the publication of the document, this topic has become a broad area of research. Below is a presentation of the key findings on the specific issues that will be addressed in their paper. In some cases, this entry uses the terminology currently accepted in this area and not the original terminology used by the authors. The term Byzantine was first used for this kind of failure in a pioneering document by Lamport, Pease and Shostak, which formulated a consensus problem regarding Byzantine generals. This article presents the algorithm that solves the problem of the Byzantine general first described in 1982 by Lamport, Pease and Shostak . Although Lamport`s algorithm is not particularly complex, it can be difficult for programmers who are not used to working on distributed calculations to implement them. To accompany the explanation of the algorithm, I included a program to experiment with the solution. You can see that in the first place, the values of paths 17 and 16 are placed at X.
In the first round, the two flawed processes may have communicated false values to all other processes and may have arbitrarily altered the values sent to different processes to distort the results. The problem of reaching a Byzantine consensus was conceived and formalized by Robert Shostak, who called it a problem of interactive coherence. This work was done in 1978 as part of the NASA-sponsored SIFT project at the Computer Science Lab at SRI International. Sift (for Software Implemented Fault Tolerance) was the child of John Wensley`s brain and was based on the idea of using several versatile computers that would communicate in pairs of messages to reach consensus, even if some of these computers were defective. Byzantine errors are considered the most common and difficult class of errors among error modes. The Fail-Stop-Fail mode takes the simplest end of the spectrum. While fail-stop error mode simply means that the only way to reach the defect is a node crash detected by other nodes, Byzantine errors do not involve constraints, meaning that the undone node can generate any data, including data that make it appear as a functional node. Thus, Byzantine errors can confuse error detection systems, making the margin of error more difficult. Despite the analogy, a Byzantine failure is not necessarily a security problem with hostile human interventions: it can be the result of electrical or software errors. What is typical of this story about computer systems is that computers are the generals and their digital communication system links that are the messengers.
Although the problem is formulated by analogy as a decision and security problem, it cannot be solved in electronics by cryptographic digital signatures, as errors can spread like false tensions through the encryption process. As a result, one component may appear defective for one component and defective for another, thus preventing a consensus on whether the component is defective or not. This problem-solving protocol is called the Byzantine Memorandum of Understanding. For entry i xi, i ε [1, n] and certain parameters d (convention) in Byzantine agreements or their achievements, the following conditions must be met: in case of Byzantine error, a component such as a server may appear inconsistent both as a defective and functional defect detection system with different symptoms compared to different observers.