How Does the Concept of “Proof-of-Work” Relate to Securing a Blockchain?

Proof-of-Work (PoW) is a consensus mechanism requiring miners to expend computational effort to solve a complex mathematical puzzle. The successful miner validates new transactions, bundles them into a block, and adds it to the chain.

This computational cost makes it economically infeasible for a malicious actor to gain control and rewrite the history of the chain.