# Questions tagged [byzantine]

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### Is this simple Asynchronous Byzantine Consensus Protocol correct?

I'm trying to solve a problem that may arise in a system I am concerned with. It will be uncommon in practice, so I am more concerned about simplicity and correctness than performance. I have N ...
80 views

### Two Generals' Problem Definition

I've read various descriptions of the TGP, most of which seem vague or conflicting on the precise constraints of the problem. Specifically: is it always or sometimes impossible to reach consensus ...
72 views

### Why is a threshold determined for Byzantine Fault Tolerance of an "Asynchronous" network? (where it cannot tolerate even one faulty node)

In following answer (LINK: https://bitcoin.stackexchange.com/a/58908/41513), it has been shown that for Asynchronous Byzantine Agreement: "we cannot tolerate 1/3 or more of the nodes being ...
305 views

### Do arbitrary/Byzantine failures include omission failures and timing failures?

Distributed Systems 5ed by Coulouris says on p68 2.4.2 Failure Models Omission Failures ... Arbitrary Failures The term arbitrary or Byzantine failure is used to describe the worst ...
49 views

### Byzantine Generals Problem - Regular Set of Neighbors

Going through Lamport's paper, I'm a little confused by the second part of the regular set of neighbors definition. A set of nodes $\{i_1, \ldots, i_p\}$ is said to be a regular set of neighbors ...
86 views

### Byzantine Generals Problem - Oral and Signed Messages

Having just read through Lamport's paper, I was hoping someone could clarify a few things on the Oral and Signed message algorithms. Why do we have to run $OM()$, recursively by $m$? If a majority of ...
23 views

### Are Physical 2-Person Lock Systems Informed by The Byzantine Generals Problem

The Byzantine Generals Problem says a set of generals who are greater than 2/3rds loyal is required to guarantee that securely issuing an order is possible the loyal generals. Because of this, I am ...
65 views

### Running Time of Oral Messages Algorithm OM(m) for Byzantine Generals Fault Tolerance

Let us consider a byzantine generals problem assuming: less than 1/3 of generals are traitors Oral messages No Crypto One solution is the Oral Message algorithm OM(m), m being the maximum number ...
256 views

### Why is Byzantine Generals Problem with traitors possible?

My question is what makes the Byzantine Generals Problem possible to solve in some cases where traitors exist, for example in the case where there are 4 generals with 1 traitor? If the generals must ...
77 views

### Why is a primary node needed in pBFT algorithm for consensus?

Why is primary needed in pBFT algo? Since many issues of viewchange etc. come up because primary may be faulty - is it possible to have a version of pBFT which doesn't have nodes assigned as primary? ...
37 views

### Can someone clarify Invariant 4.7 of the PBFT correctness proof paper?

I am reading the PBFT Correctness Proof Paper and I cannot make completely sense of the Invariant 4.7 and its proof: Here are my concerns: I assume that the symbol $\Leftrightarrow$ is used with the ...
57 views

### Number of replicas needed for fault tolerance in state machine replication

I am trying to get my head around "State Machine Replication". I understand that it is a way to ensure resilience against failures. I have read that in order to provide fault tolerance against normal ...
54 views

### Enforcing application layer consensus on top of a distributed consensus protocol

If I understand correctly, the term "consensus" in distributed consensus algorithms means that all the participants ("peers") achieve a common understanding of some data value. Different algorithms ...