Monero adopted the CryptoNote protocol technology family for its privacy-focused cryptocurrency design.
Monero launched in April 2014 as a fork of Bytecoin, which was the first publicly released cryptocurrency based on CryptoNote. CryptoNote described cryptographic techniques intended to make transactions difficult to link to users and to conceal transaction amounts. Monero’s early codebase inherited this technology and developed it further.
Monero uses privacy mechanisms including stealth addresses, ring signatures, and confidential transactions. These features are designed to obscure the recipient, the sender’s contribution among a group of possible signers, and the amount transferred. The exact implementation has changed through subsequent upgrades, so CryptoNote is best understood as the foundational protocol family rather than a complete description of modern Monero.
CryptoNote is often confused with CryptoNight, the proof-of-work hashing algorithm used by early versions of Monero. They are related historically but are not the same thing: CryptoNote refers to the privacy-oriented protocol design, while CryptoNight refers to a mining algorithm.