Bitcoin is built on a distributed digital record called a blockchain. As the name implies, blockchain is a linked body of data, made up of units called blocks that contain information about each and every transaction, including date and time, total value, buyer and seller, and a unique identifying code for each exchange. Entries are strung together in chronological order, creating a digital chain of blocks.
“Once a block is added to the blockchain, it becomes accessible to anyone who wishes to view it, acting as a public ledger of cryptocurrency transactions,” says Stacey Harris, consultant for Pelicoin, a network of cryptocurrency ATMs.
Blockchain is decentralized, which means it’s not controlled by any one organization. “It’s like a Google Doc that anyone can work on,” says Buchi Okoro, CEO and co-founder of African cryptocurrency exchange Quidax. “Nobody owns it, but anyone who has a link can contribute to it. And as different people update it, your copy also gets updated.”
While the idea that anyone can edit the blockchain might sound risky, it’s actually what makes Bitcoin trustworthy and secure. In order for a transaction block to be added to the Bitcoin blockchain, it must be verified by the majority of all Bitcoin holders, and the unique codes used to recognize users’ wallets and transactions must conform to the right encryption pattern.
These codes are long, random numbers, making them incredibly difficult to fraudulently produce. In fact, a fraudster guessing the key code to your Bitcoin wallet has roughly the same odds as someone winning a Powerball lottery nine times in a row, according to Bryan Lotti of Crypto Aquarium. This level of statistical randomness blockchain verification codes, which are needed for every transaction, greatly reduces the risk anyone can make fraudulent Bitcoin transactions.