What is a Byzantine Fault Tolerance (BFT)?

Byzantine Fault Tolerance (BFT) is an important resilience system that is used in distributed computing systems. It ensures that if a system is attacked, the system will continue to work, despite the attack.

BFT helps to ensure that the system will always be able to handle any potential attack, such as those caused by malicious users or faulty hardware or software. BFT is an algorithm that allows a distributed system to remain resilient and consistent, even when some of its components fail. It is used in distributed systems to help ensure that the system is always able to maintain its consistency and integrity.

In order for a system to be Byzantine Fault Tolerant, it must be able to handle any attack regardless of its origin. This means that the system must have the ability to detect and recover from any type of attack, regardless of the origin.

The algorithm for Byzantine Fault Tolerance works by allowing each node in the system to always have the most up-to-date information. This ensures that the information is always accurate and that the system will remain consistent and resilient even when it is attacked.

Byzantine Fault Tolerance is often used in financial systems, to ensure that the transactions are always accurate and secure. It is also used in distributed computing systems, to ensure that the system is always able to remain consistent, even when there are components that fail.

Simple Example

Byzantine Fault Tolerance can be thought of as a group of people trying to make a decision together, but some members of the group may not have the same information or may deliberately provide false information. In order to reach a correct decision despite these potential problems, the group uses a series of rules and checks to ensure that the information provided by each member is trustworthy and that the final decision made is the correct one. In the same way, Byzantine Fault Tolerance is used in computer systems, such as blockchain, to ensure that data is processed correctly even when some of the components of the system are unreliable or providing false information.

Who Invented the Byzantine Fault Tolerance (BFT)?

Leslie Lamport, a renowned computer scientist, made groundbreaking contributions to the field of distributed systems and introduced the concept of Byzantine Fault Tolerance (BFT) in a seminal paper published in 1982. Lamport's pioneering work aimed to address potential failures in computer systems when certain components malfunction or present conflicting information, a problem akin to the Byzantine Generals' Problem. This theoretical scenario involved a group of generals surrounding a city, coordinating their attack or retreat through messengers, with the possibility of traitorous messengers relaying false information. Lamport's concept of Byzantine Fault Tolerance established a mechanism to safeguard against these failures, ensuring the system could function robustly even in the presence of potentially malicious components or erroneous data.

Lamport's influential research laid the groundwork for the development of fault-tolerant distributed systems, offering solutions to overcome Byzantine failures and maintain consensus among distributed nodes. His work profoundly impacted the design and implementation of secure and reliable computer networks, providing a framework for achieving consensus and reliability in systems prone to malicious attacks or faulty behavior. The term "Byzantine Fault Tolerance," coined by Lamport, has become a cornerstone concept in the realm of distributed computing, shaping the way engineers and researchers approach the reliability and security of decentralized systems.


Sybil Attack: BFTs are still vulnerable to Sybil attacks, where one party is able to get control of a large portion of nodes. The more nodes the actor has control over, the easier it is to launch a Sybil attack.

Consensus Mechanisms: Popular Consensus Mechanisms like proof-of-work and proof-of-stake have byzantine fault tolerance, even though a miner or validator fills his block with invalid transactions, for the block to be appended to the chain, it needs confirmation from other validators. Penalties such as loss of staked assets can be awarded to rogue validators.

  • Byzantine General Problem: The Byzantine General Problem is a computer science problem that arises in distributed computing systems. It occurs when multiple generals (or nodes) have to coordinate their actions in order to achieve a common goal.

  • Distributed Network: A distributed network in cryptocurrency refers to a decentralized system where the data, transactions, and processing power are spread across many nodes in a network, rather than being concentrated in a central location.