What is Byzantine Fault Tolerance?

2 August 2023

8m read

Similar to the majority of distributed computing systems, a cryptocurrency network's users must regularly reach an understanding of the blockchain's status. This is known as consensus achievement. However, achieving distributed network consensus in a secure and effective manner is far from simple.
How then can a dispersed network of computer nodes reach a consensus if some of the nodes are prone to malfunction or engage in dishonest behavior? The so-called Byzantine Generals' issue, which gave rise to the idea of Byzantine fault tolerance, has this as its central question.

What Issue Affects the Byzantine Generals?

The conundrum presupposes that each general has their own army and that they are dispersed throughout the city they wish to attack. In order to attack or retreat, the generals must come to an agreement. They can assault or retreat as long as all generals come to an agreement, or agree on a course of action so that it can be carried out in unison.
As a result, we might take into account the following requirements:
Each general must choose whether to assault or retreat (yes or no), and once a choice has been made, it cannot be altered. All generals must also agree on the same choice and carry it out in unison.
One general can only speak with another through messages that are delivered by a courier, which contributes to the aforementioned communication issues. Because of this, the primary difficulty in solving the Byzantine Generals' Problem is that messages may be somehow lost, damaged, or delayed.
Additionally, even if a message is successfully delivered, one or more generals could decide to act maliciously and send a false message to confuse the other generals for whatever reason, which would result in a complete failure.
Each general symbolizes a network node in the context of blockchains, and the nodes must come to an agreement on the system's current status. To put it another way, in order to prevent total failure, the majority of participants within a dispersed network must concur and carry out the same activity.

The BFT (Byzantine Fault Tolerance) code is

Byzantine fault tolerance (BFT), in a nutshell, is the ability of a system to withstand the class of failures resulting from the Byzantine Generals' Problem. This indicates that a BFT system can function even if some nodes fail or behave maliciously.
There are various ways to construct a BFT system since there are various ways to solve the Byzantine Generals' Problem. The so-called consensus algorithms are one way that a blockchain can achieve Byzantine fault tolerance, and there are other methods as well.

Consensus algorithms for blockchain

The PoW consensus method determines how these rules will be adhered to in order to establish consensus; for example, during the verification and validation of transactions.

Concluding remarks

The intriguing conundrum known as the Byzantine Generals' Problem eventually led to the development of the BFT systems, which are now widely used in many different contexts. A few use applications for BFT systems outside the blockchain sector include the nuclear power, aerospace, and aviation sectors.
In the context of cryptocurrencies, a strong consensus mechanism and effective network connectivity are essential components of any blockchain ecosystem. These systems' security requires ongoing work, and the current consensus methods still have several problems to solve (such as scalability). However, as BFT systems, PoW and PoS are very intriguing techniques, and the potential applications undoubtedly spur broad innovation.

Latest Releases