Cryptocurrency is trustless because of blockchain, the underlying technology that drives it.
Blockchain works by linking blocks of information together with a mathematical formula that ensures they are all in the correct order. It uses cryptography to scramble information, ensuring that the information can’t be decoded without the right key.
This means that it is not possible for someone to tamper with a block in the chain after it has been created. It is also impossible for someone to create a block in the chain and put it back somewhere else after it has already been made, since each block is linked to the one before it, and an individual block cannot be altered once it has been built.
The Blockchain is accessible to everyone everywhere, allowing anyone to look into any transaction ever made in the network, making it go against the very nature of Bitcoin’s privacy.
Blockchain is a shared, immutable ledger for recording the history of transactions. It fosters a new generation of transactional applications that establish trust, accountability and transparency—from contracts to deeds to payments.
With the combination of the public nature of the transactions and their immutability, it becomes almost impossible to defraud users through tampering, double-spending or other means.
The most dominant cryptocurrency solutions to date are centralized, and as such they are vulnerable to traditional hacking methods and more intentional abuse of power. Blockchain, decentralized systems, and eventually distributed ledgers are poised to disrupt the existing system architecture that cryptocurrencies have become dependent on. The only question is: when?