What is byzantine fault tolerance blockchain?

Since the advent of Bitcoin in 2008, along with its decentralized digital currency system. Various other cryptocurrencies have also emerged with their own unique mechanisms. Nonetheless, the common thread among these projects is the element of consensus within the Blockchain. With the exception of a few outliers, the majority of Blockchains are designed to achieve a decentralized nature, operating as an electronic ledger. Distributed computer nodes play a vital role in maintaining network functionality. Consequently, Blockchain technology provides reliable and transparent transactions without the need for intermediaries. Payment systems and traditional banking institutions are gradually adopting crypto as a feasible alternative solution. However, one of the core issues of a distributed computing system is the consensus of the participants in the network, such as achieving agreement on the current state of the Blockchain or changes in storage, bandwidth, and gas fees. Achieving quick consensus on a distributed network has never been easy, so what is the solution to this problem? How can nodes quickly reach an agreement on the current state of the network? Is there a scenario where nodes could cause harm to the network? This is where it becomes essential to have a thorough understanding of the Byzantine Generals problem and the concept of the Byzantine fault-tolerant system in order to effectively address these issues.

Byzantine Fault Tolerance – What is Byzantine fault tolerance blockchain?

The designation BFT refers to a system that can operate continuously despite the occurrence of errors. It was named Byzantine Fault Tolerance because it addresses a problem frequently encountered by Byzantine generals. When BFT is implemented in a Blockchain application, the system can still function even if some nodes are faulty or if harmful actions are taken on the network. Therefore, BFT plays a critical role in ensuring the continuity of Blockchain operations. Nowadays, various popular Blockchains are gradually developing their own distinctive consensus algorithms in order to achieve a Byzantine fault-tolerant system.

The Byzantine general’s math problem

The BFT problem emerged in 1982 as an endeavor to describe a logical conundrum with two propositions. Specifically, the issue entailed a group of Byzantine generals attempting to establish communication to attain agreement on their next course of action. The assumption of the problem is that each general has their own army, stationed at various locations around the city where a battle is taking place. To achieve victory, they must reach a consensus on whether to attack or retreat. Essentially, whether to attack or retreat is not important. The key point is that all the generals must agree on a common decision to coordinate their actions. In other words, there is a need for a unified approach where either all the generals attack together, or they all retreat together. This must be agreed upon by the generals in their respective positions around the city.

We can consider a number of objectives as follows:

• Every commander must make a decision regarding whether to engage in an attack or to retreat.
• Once a decision has been executed, the commanding officer is not authorized to alter it.
• It is imperative that all commanding officers reach a unanimous decision and execute it in a synchronized manner.

Undoubtedly, in reality, military commanders can communicate with each other through the intermediaries. However, the risk of message transmission includes the possibility of delay or loss. Even if the messages have reached the hands of the commanders, the detrimental decisions made by certain unscrupulous commanders can still cause disturbance and lead to failure. When applying this problem to Blockchain, each commander can represent one Node, and the agreement on the current state is something that every Node must ensure. To prevent failure, the majority of participants in the decentralized network must agree and carry out the same action. In order to achieve success, it is imperative that the nodes of a network be both truthful and reliable. Requiring consensus from at least ⅔ or more of the participants. If the majority of decisions made within the network are harmful, the system may be vulnerable to attack or errors, exemplified by the 51% attack.

Compare Centralized vs Decentralized

The issues faced by the Byzantine tend to arise within centralized or decentralized systems

As it is widely acknowledged, a centralized system demands an organization or agency to undertake the responsibility of managing and supervising it. This implies that published information is accurate and legitimate, provided by a competent authority. Consequently, fraudulent or false information can be prevented or hindered from spreading throughout the network. Thus, achieving consensus becomes more feasible. The issue becomes significantly more challenging with a decentralized system, as there is no designated organization or entity responsible for managing and monitoring the system. Consequently, the veracity of the information sources cannot be verified with certainty, making it difficult for network members to establish trust in the system. For the purpose of clarification, let us consider the example of traditional financial institutions, namely banks. We often have several reasons to trust banks in the storage and transaction of assets. In a scenario where a bank engages in fraudulent behavior towards customers, it is the central bank or government agencies that step forward to rectify such actions.

How Bitcoin Solves the Byzantine Fault Tolerance Blockchain

As previously analyzed, the Byzantine Fault Tolerance (BFT) problem is more prevalent in decentralized systems than in centralized ones. Cryptocurrency ecosystems operate mostly in decentralization. Hence, the challenge is for the Blockchain technology to address this issue. The algorithms used to establish trust between nodes in blockchain projects depend on the characteristics of the blockchain being utilized. In the case of Bitcoin, the Proof of Work consensus algorithm is utilized to address this issue. This algorithm establishes a set of objective and transparent principles that govern the system. To add a Block to the Blockchain, a member of the network is required to provide relevant evidence to prove that the results they have achieved are based on their own effort. This process entails significant costs for the creator team, while also encouraging them to publish information honestly.

How fault tolerant are consensus algorithms?

Although users may not know each other’s identities, the principles of Bitcoin’s network are objective and free from intervention or disagreement with the information on it. Furthermore, once a Block is added to the Blockchain, it is virtually immutable, meaning it is difficult to remove and Bitcoin’s past is inviolable and unchangeable. Based on this characteristic, the participants in the network can grasp and synchronize the state of the Blockchain at all times. Consequently, they are also able to verify and agree on the transactions within the Block. As per the requirements of the Proof of Work, each Node is responsible for verifying on their own or relying on specific criteria to determine the validity of the blocks.

In the event that a member of the network attempts to propagate false information, the remaining nodes on the network can immediately recognize it and disregard it. Transparency is intrinsic to all nodes in Bitcoin, allowing any node to verify all information on the network. Put simply, all nodes possess the most transparent and accurate source of information, thereby obviating the need to rely on third-party individuals or organizations. This is precisely what gives Bitcoin the characteristic of being a trustless system, meaning that it is a system that does not require users to trust one another. Naturally, the POW algorithm cannot guarantee absolute resistance to Byzantine faults. However, another characteristic of POW is its high cost in encryption technology and coin mining processes. This factor contributes to the reliable security and utmost safety of Blockchain networks provided by POW.

In addition to POW, several other algorithms have been developed and introduced to ensure various factors such as scalability alongside problems relating to Byzantine. These include POS – Proof of Stake, POA – Proof of Authority, amongst others.

Special feature of byzantine fault tolerance

One of the distinctive features of BFT is its ability to reach consensus even in the presence of certain disagreements between two nodes. This characteristic is particularly crucial for decentralized Blockchains like Bitcoin or Ethereum. Satoshi Nakamoto, the creator of Bitcoin, has made a significant breakthrough in addressing the BFT (Byzantine Fault Tolerance) issue. By implementing proof of work for the Bitcoin network, the system can protect itself from malicious nodes, effectively reducing the number of such nodes by up to a third.

Pros and cons of Byzantine Generals Problem

Advantage

• The Byzantine Generals Problem does not impose any requirement in terms of energy consumption or algorithmic power. This is because no miners are obligated to solve complex algorithms for every transaction block. As a result, the consensus process can be conducted in a more friendly manner compared to the Proof of Work approach.
• If all Nodes come to an agreement regarding a transaction block, it will be confirmed immediately without the need for multiple confirmations.
• As every node is capable of participating in actions, rewards can also be shared among all participants. In this context, the rewards allocated to nodes will not differ as in POW or POS.

Defect

• By means of this approach, it is possible for one party to acquire a significant level of control over a substantial quantity of Nodes, which could result in the occurrence of Sybil attacks.
• This method also takes longer and has limited scalability due to the requirement for nodes to communicate with each other at every step of the process.

With the aforementioned insights, it is likely that you have grasped the fundamental knowledge needed to comprehend what Byzantine fault tolerance entails, as well as its significance in the realm of Blockchain. Additionally, you can understand how Bitcoin has addressed this issue and stabilized the Blockchain system. Based on this, you can efficiently evaluate a Blockchain and its operational aspects.