Questions tagged [byzantine]
18 questions
5
votes
1 answer
What is the algorithm for Blockchain's Byzantine Fault Tolerance?
This person was asked: "Why is a blockchain implementation different than a distributed consensus system like Raft?"
In part of their answer they replied:
For one, Raft is not Byzantine fault tolerant, i.e., not designed to account for arbitrary…
hawkeye
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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? Or does having a primary node fulfill a function…
pranay01
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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 nodes that I want to reach agreement on a boolean…
user1055568
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2
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1 answer
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 dishonest or we lose
either safety or liveness."
For…
Questioner
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2 answers
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 either all attack or all retreat at the same time,…
bkoodaa
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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 usual meaning of double…
Robbo
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vote
0 answers
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 failures it can be derived that, there must be…
Casper343
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1 answer
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 can handle different types of failures or…
Duncan
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1
vote
2 answers
Two Generals' Problem - Thought Experiment
After reading the Two Generals' Problem, I am wondering as to why there isn't any solution and please correct me if I am missing something.
What if, the generals decide that they will attack if they receive at least two confirmations from each…
ARGYROU MINAS
- 111
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vote
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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 of a node if :
each $i_j$ is a neighbor of…
JToya
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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 the Lieutenants are loyal, do they not get the…
JToya
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0 answers
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 curious why so many physical systems opt for…
user107916
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1 answer
Is there a usable implementation of PBFT?
In the original Practical Byzantine Fault Tolerance (PBFT) paper they mention they implemented a fault tolerant NFS service. To do that they made a library for PBFT. Does that exist anywhere?
As that paper is quite old now and was well received, I…
Leonidaz0r
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0
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1 answer
Where is found the original library of the PBFT consensus algorithm?
In the PBFT paper written by Miguel Castro it has been mentioned:
(In Abstract:)
"BFT has been implemented as a generic program library with a simple
interface."
(Also in page 71:)
"The algorithm has been implemented as a generic program library…
Questioner
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0
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How does PBFT tolerate Byzantine Leaders?
It is said that PBFT (or Practical Byzantine Fault Tolerance consensus) is Byzantine fault tolerant (unlike Paxos or Raft that are only Crash fault tolerant.)
Based on this answer : LINK , in PBFT "a new leader is elected only if there is a…
Questioner
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