Proof of Work
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In Brief
Proof of Work (PoW) is the original blockchain consensus mechanism, used by Bitcoin, in which miners compete to solve a computationally intensive puzzle to validate transactions and earn the right to add the next block.
What Is Proof of Work?
Proof of Work (PoW) is the original consensus mechanism that secures blockchains like Bitcoin. It requires participants — called miners — to expend real computing power to solve a difficult mathematical puzzle. The first to solve it earns the right to add the next block and receives a reward.
The "proof" is that solving the puzzle is hard and resource-intensive, but verifying the solution is easy. This makes it extremely costly to attack the network, because doing so would require an enormous amount of computing power.
How Does Proof of Work Work?
Miners collect pending transactions into a candidate block.
They repeatedly hash the block data with a changing value (the nonce) to find a hash below a target threshold.
Finding a valid hash requires trillions of attempts — this is the "work."
The first miner to find a valid solution broadcasts the block to the network.
Other nodes easily verify the solution and accept the block.
The miner receives the block reward plus transaction fees.
Why Is Proof of Work Secure?
Costly to attack — controlling the network would require more than 50% of all mining power (a "51% attack"), which is prohibitively expensive on large networks.
Tamper resistance — altering a past block would require redoing all the work for that block and every block after it.
Decentralization — anyone with hardware can participate, and no central party controls block production.
Proof of Work vs Proof of Stake
| Feature | Proof of Work | Proof of Stake |
|---|---|---|
| How blocks are added | Solving a puzzle | Validators chosen by stake |
| Security backed by | Computing power + energy | Locked-up capital |
| Energy use | High | Low |
| Hardware | Specialized (ASIC/GPU) | Standard computer |
| Examples | Bitcoin, Litecoin, Dogecoin | Ethereum, Solana, Cardano |
The Energy Debate
Proof of Work's main criticism is its high energy consumption, since security comes from the real-world cost of electricity and hardware. Supporters argue this same cost is precisely what makes PoW networks like Bitcoin so secure and resistant to manipulation, while a growing share of mining uses renewable and otherwise wasted energy.
Proof of Work and Trust Wallet
Trust Wallet lets you store and manage coins secured by Proof of Work, such as Bitcoin and Litecoin. As a non-custodial wallet, you control your private keys and your funds at all times. You can send, receive, and track PoW assets in real time, alongside 10,000+ other cryptocurrencies across 100+ blockchains.