Читать книгу Cryptocurrency Mining For Dummies - Peter Kent - Страница 49

For a cryptocurrency to function, several conditions must be met by the protocol. We like Jan Lanksy’s six-factor list (Jan is a cryptocurrency academic, teaching at a university in the Czech Republic). Mining (in the mineable cryptocurrencies; nonmineable currencies have different mechanisms) is an integral part of making sure these conditions are met:

 The system doesn’t require a central authority and is maintained through distributed consensus. That is, everyone agrees on the balances associated with addresses in the blockchain ledger. Mining is an integral part of adding transactions to the blockchain and maintaining consensus.

 The system keeps track of cryptocurrency units and their ownership. Balances can be proven at any point in time. Mining adds transactions to the blockchain in a way that becomes immutable — the blockchain can’t be changed. If the blockchain shows your balance is five Bitcoin, then you absolutely do own five Bitcoin!

 The system defines whether new cryptocurrency units can be created, and, if so, the system defines the circumstances of their origin and how to determine the ownership of these new units. A fixed issuance or inflation rate is predefined. Mining provides a way to release new cryptocurrency into circulation at a predetermined, controlled rate, with ownership being assigned to the miner.

 Ownership of cryptocurrency units is proved through cryptography. The three conditions of authenticity, nonrepudiation, and immutability are met, through the use of cryptography. Miners, using cryptography, verify that transaction requests are valid before adding them to a new block. The miner verifies that the transaction request is for a sum that is available to the owner of the crypto, that the owner has correctly signed the request with their private key to prove ownership, and that the receiving address is valid and able to accept the transfer.

 The system allows transactions to be performed in which ownership of the cryptographic units is changed. Transactions can be submitted only by senders who can prove ownership of the cryptocurrency being transferred. Cryptocurrency owners prove ownership by signing transactions using the addresses associated with a private key. Mining is the process through which transactions are accomplished, and miners verify ownership before adding the transaction to the blockchain.

 If two different instructions for changing the ownership of the same cryptographic units are simultaneously entered, the system performs at most one of them. Double-spending the same unit is not possible. The problem of double-spending was one that weakened earlier digital currencies. But with modern cryptocurrencies, miners vet transactions, searching the blockchain record of transactions to determine whether the owner actually has sufficient balance at that moment. If a sufficient balance isn’t accounted for within the spend address (the Input address) in the transaction request, the transaction will be rejected by the node software and never mined onto the blockchain. Also, if the same sender has two or more pending transaction requests, but doesn’t own enough cryptocurrency to cover them all, miners can decide which of the requests is valid. Additional transactions will be discarded to avoid double-spending the same currency.

If even one of these six conditions isn’t met, a cryptocurrency will fail because it can’t build enough trust for people to reliably use it. The process of mining solidifies and satisfies every single one of these conditions.