What Is the "Longest Chain Rule" and How Does It Relate to Block Confirmation? ▴ Learn

What Is the “Longest Chain Rule” and How Does It Relate to Block Confirmation?

The longest chain rule (or Nakamoto Consensus) is the mechanism by which nodes in a Proof-of-Work network agree on the single, authoritative history of transactions. Nodes always consider the chain with the most cumulative proof-of-work (the "longest" or heaviest chain) as the valid one.

A transaction is considered confirmed only when the block containing it is buried under a sufficient number of subsequent blocks on this longest chain, making it practically irreversible.

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