Overview
The longest chain rule is a fork choice rule favoring the chain with the most accumulated proof of work, used by Bitcoin. Nodes follow the chain that has the most work behind it. It provides a simple way to resolve forks.
How It Works
Miners build on the chain they consider canonical, which is the one with the most accumulated difficulty. When a competing chain becomes longer, miners switch to it. This rule assumes the majority of hash power is honest.
Why It Matters
The longest chain rule is simple and effective for proof-of-work networks, providing probabilistic finality. It is the foundation of Bitcoin's security model. Its simplicity contrasts with more complex rules in proof-of-stake systems.
Related Concepts
The Longest Chain Rule is a type of Fork Choice Rule central to Proof of Work. It provides Probabilistic Finality.