POW: Proof of Work
Originally implemented to deter spam and denial of service attacks. The Proof of Work concept was subsequently adapted to the purpose of securing digital assets using the SHA-256 hashing algorithm by Hal Finney. Upon launch Bitcoin became the first application to incorporate the concept and he was honored as the recipient of the first Bitcoin transaction.
What is POW?
Decentralized peer to peer consensus mechanism cryptoassets use to group transactions and add them as blocks to their networks.
The mining process is an arbitrary, yet computationally intensive search for a nonce. That can be combined with the candidate block’s Merkle Tree and block header to find a hash the network will confirm as valid.
This hash is the output, demonstrating the input of computational power expended by the miner. During the race to discover a new block for the network, i.e. Proof of Work.
The high level of computational power required secures the blockchains records and makes them difficult to manipulate. Energy expenditure is an important component of this intensity.
The expenditure required to initiate an attack and attempt to alter a blockchains’s transaction history is usually so high. There is no economic justification for even trying.
Since generating hashes is a minor technical challenge for computers nowadays. Proof of Work blockchains employ difficulty levels to target a fixed rate of block adds to their networks.
10 minutes for bitcoin / 2.5 minutes for Litecoin.
With the level of difficulty rising as the power devoted to mining the network expands. To ensure advances in computation do not lead to shorter block times than intended for the network.
Further Reading Proof of Work
SHA-256 Cryptographic Hash Algorithm