Bitcoin is a decentralized digital currency, without a central bank or single administrator, that can be sent from user to user on the peer-to-peer bitcoin network without the need for intermediaries. Transactions are verified by network nodes through cryptography and recorded in a public distributed ledger called a blockchain
Bitcoin is unique in that there are a finite number of them: 21 million.
Satoshi Nakamoto, bitcoin’s enigmatic founder, arrived at that number by assuming people would discover, or “mine,” a set number of blocks of transactions daily.
Every four years, the number of bitcoins released relative to the previous cycle gets cut in half, as does the reward to miners for discovering new blocks. (The reward right now is 12.
As a result, the number of bitcoins in circulation will approach 21 million, but never hit it.
This means bitcoin never experiences inflation. Unlike US dollars, whose buying power the Federal Reserve can dilute by printing more greenbacks, there simply won’t be more bitcoin available in the future.
That has worried some skeptics, as it means a hack could be catastrophic in wiping out people’s bitcoin wallets, with less hope for reimbursement. Which could render bitcoin price irrelevant.
Yet while the price and adoption of Bitcoin and Ethereum will continue to grow as more people learn about them and use them every day, both cryptocurrencies will face challenges that could trip them up.