The technology underpinning the functioning of cryptocurrencies is called blockchain. This decentralized technology allows cryptocurrencies to operate securely without the need for intermediaries like banks. Blockchain's transparent ledger records all transactions, ensuring that they cannot be maliciously altered or tampered with. Each transaction is confirmed by network participants (miners), fostering trust and security. Cryptocurrencies leverage blockchain's features for peer-to-peer transactions, paving the way for innovations in financial systems and beyond.