In a Proof of Work (PoW) system, what is required from the nodes?

In a Proof of Work (PoW) system, the primary requirement from the nodes is to perform heavy calculations. This process involves solving complex mathematical problems to validate transactions and secure the blockchain. Each node, often referred to as a miner, competes to be the first to find a solution to the computational puzzle. Successfully solving this puzzle allows the miner to add a new block to the blockchain and receive rewards in the form of cryptocurrency.

This intensive computational effort is crucial for maintaining the integrity and security of the network, as it makes it difficult for malicious actors to alter any part of the blockchain. The heavy calculations serve to deter fraudulent activities and ensure that the network remains decentralized and trustworthy. By requiring substantial computational power, it also prevents spam and attacks on the network.

Maintaining a record of all transactions, validating user identity, and providing funding are not specific to the PoW mechanism itself but are part of the broader functions that a blockchain network may perform. Therefore, while these aspects may play roles in a blockchain's operations, they do not define the fundamental requirement of nodes in a PoW system, which is to engage in the heavy calculations necessary for consensus.