A proof-of-work system is designed as a deterrent to spamming or denial of service attacks by requiring the expenditure of typically computational processing power. This computational work represents an economic cost which an attacker would have to waste in order to disrupt the network. A core aspect of any proof-of-work system is that it is difficult to produce an output (proving work was done sacrificing some sort of economic value) and is easy for others to verify the work was completed without performing the work again themselves.
Usage in blockchain
The Bitcoin blockchain uses a proof-of-work system derived from hashcash created by Adam Back. For a node to propose a block onto the blockchain, it must find a nonce (an arbitrary number that can only be used once) that prepends to the block and results in a hash within a small range. Bitcoin blockchain adjust the size of this range such that every block created globally has about 10 minutes interval.
Proof of Stake versus Proof of Work
Sybil attack: concepto fundamental de la blockchain
February 28, 2018
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- EthereumEthereum is an open-source, public, distributed blockchain computing platform featuring smart contract (scripting) functionality, which facilitates online contractual agreements.
- Proof-of-stakeProof-of-stake (PoS) is a system by which a network (e.g., a cryptocurrency blockchain) aims to achieve distributed consensus.
- BlockchainA blockchain is an append-only digital ledger storing a set of time-ordered transactions grouped in blocks that are linked together using cryptographic hashes.
- BitcoinBitcoin is a cryptocurrency and a digital payment system invented by an unknown programmer, or a group of programmers, under the name Satoshi Nakamoto. It was released as open-source software in 2009.
- CryptocurrencyA cryptocurrency (or crypto currency) is a digital asset designed to work as a medium of exchange using cryptography to secure the transactions and to control the creation of additional units of the currency. Cryptocurrencies are a subset of alternative currencies, or specifically of digital currencies.
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