One-sentence definition:
Proof of work is used in blockchain systems where miners must solve computationally difficult puzzles to validate transactions and create new blocks, making it costly to attack the network.
Why it matters:
It matters because it shows where work was done and no one lied about it. Without the PoW, thousands of fake identities would be created.
Example:
Proof of work makes rewriting history computationally expensive while letting anyone verify it instantly.
Links:
- Basics post: “What is a hash and why does it matter?”
- Related glossary term: Mining