Algorithm

An algorithm is a defined set of step-by-step rules used by computers to perform calculations, solve problems, or complete tasks. In cryptocurrency and blockchain systems, algorithms are everywhere, from turning data into cryptographic fingerprints to coordinating how a global network agrees on a single transaction history.

Many core blockchain functions rely on cryptographic algorithms. A common example is a hash function, which takes any input, such as a transaction or a block header, and transforms it into a standardized output of fixed length. The output generally looks random and is not practically reversible, which helps make tampering obvious. If even one character of the input changes, the resulting hash changes dramatically, so nodes can quickly detect altered data. Digital signature algorithms similarly allow users to prove ownership of funds by signing transactions with a private key, while others verify the signature with a public key.

Blockchain consensus algorithms are special because they determine how decentralized nodes resolve disputes, such as when different nodes receive conflicting data or propose different blocks. Proof of Work and Proof of Stake are well-known consensus algorithms that specify how blocks are proposed, how the network chooses the valid chain, and what economic costs or incentives discourage dishonest behavior. In practice, these rules govern transaction validation, block creation, and finality expectations across the network.

Beyond consensus and cryptography, algorithms also drive wallet software, fee estimation, transaction propagation rules, and smart contract execution. Each component follows precise instructions so different computers can reach consistent results.