{"id":37987,"date":"2024-05-03T17:00:00","date_gmt":"2024-05-03T14:00:00","guid":{"rendered":"https:\/\/forklog.com\/en\/?p=37987"},"modified":"2025-08-30T00:16:06","modified_gmt":"2025-08-29T21:16:06","slug":"how-various-protocols-tackle-the-byzantine-generals-problem","status":"publish","type":"post","link":"https:\/\/forklog.com\/en\/how-various-protocols-tackle-the-byzantine-generals-problem\/","title":{"rendered":"How various protocols tackle the Byzantine Generals Problem"},"content":{"rendered":"
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What is the Byzantine Generals Problem?<\/h2>\n

The Byzantine Generals Problem is a thought experiment applied to electronic distributed networks. It seeks a way to synchronise independent participants.<\/p>\n

The set-up:<\/p>\n

\u00abArmies of several generals (network nodes) are besieging a city. They can communicate only by sending messengers (transactions). The key task is to agree on a common plan to attack or retreat (consensus). Some generals are traitors and will try in every way to thwart the agreement\u00bb.<\/em><\/p>\n

The first academic paper on the topic in 1982 was published<\/a> by Leslie Lamport, Robert Shostak and Marshall Pease. The problem applies only to distributed systems without a central node trusted by the rest of the network. In the real world such a node could be, for example, a country\u2019s central bank, which issues fiat currency and allocates it to commercial banks\u2019 accounts.<\/p>\n

Because cryptocurrencies are built on decentralised principles without a single governing authority, solving this problem became foundational to the design of blockchain-based networks.<\/p>\n<\/div>\n

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How did Satoshi Nakamoto solve the Byzantine Generals Problem?<\/h2>\n

In 2008 the creator of Bitcoin, Satoshi Nakamoto<\/a>, proposed a practical solution to the Byzantine Generals Problem. He devised the Bitcoin protocol and implemented the Proof-of-Work (PoW)<\/a> consensus algorithm. This removed the need for trust by setting clear rules for achieving consensus (agreement) among Bitcoin\u2019s distributed nodes (the generals).<\/p>\n

The PoW algorithm allows each node to verify that others have done the work correctly and are abiding by the agreement. This is achieved through the blockchain, cryptography and economic incentives for miners, which protect consensus from malicious behaviour.<\/p>\n

If a node decides to perform the \u201cwrong work\u201d, other participants will see it and will not allow the unwanted activity to proceed.<\/p>\n<\/div>\n

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Which consensus algorithms do cryptocurrencies use?<\/h2>\n

Beyond Proof-of-Work, the most common and reliable solutions to the Byzantine Generals Problem are Proof of Stake (PoS) and Byzantine Fault Tolerance (BFT).<\/p>\n

Proof of Stake (PoS)<\/a> is the most popular version in the crypto market. Instead of miners, as in PoW, control of the network is given to holders of the native coin. The main advantage is far lower energy consumption compared with PoW.<\/p>\n

Byzantine Fault Tolerance (BFT) is designed to scale PoS blockchain networks. Unlike the previous approach, BFT relies on collective decision-making in reaching consensus. Nodes send transactions to one another until two-thirds of all nodes arrive at the same result.<\/p>\n

There are many modifications and hybrid algorithms. One is Tendermint, which underpins the Cosmos<\/a> blockchain, where Delegated Proof-of-Stake (DPoS) and BFT are used together. For example, Solana<\/a> uses DPoS and a BFT implementation\u2014Practical Byzantine Fault Tolerance (pBFT).<\/p>\n

\"How
Source:<\/a> 101 Blockchains<\/figcaption><\/figure>\n

Beyond these algorithms, cryptocurrencies use more than a dozen other consensus variants. Some include:<\/p>\n