Proof of Work
Definition
Proof of Work (PoW) is a blockchain consensus mechanism that requires miners to perform expensive computation in order to propose valid blocks. The work is costly to produce but trivial for others to verify.
Core Ideas
- miners search for a nonce that satisfies a difficulty target
- the network accepts blocks that demonstrate valid work
- work acts as a scarce resource that helps resist Sybil attacks
- incentives reward honest block producers through block rewards and fees
Why It Exists
The source notes connect PoW to three problems:
- how to choose who proposes the next block
- how to discourage free-for-all spam around rewards
- how to prevent many fake identities from overwhelming consensus
Main Properties
- expensive to compute
- easy to verify
- difficulty can be adjusted over time
- ties influence to computing power rather than simple identity count
Trade-Offs
- high energy use
- slow finality compared with some other systems
- concentration risk when mining becomes industrialized
Relationships
- Distributed Consensus — proof of work is one practical path to decentralized consensus
- Cryptocurrency Fundamentals — PoW is one of the key mechanisms behind Bitcoin-style blockchains
- Ethereum Development — Ethereum historically used proof of work before changing consensus models
References
- 2.4 Incentives and Proof of Work
- Coursera - Proof of Work vs Proof of Stake: Basic