Firo (FIRO), previously known as Zcoin, is a cryptocurrency that prioritizes privacy in digital transactions. It introduced the Lelantus privacy protocol, enabling users to destroy their coins and exchange them later for new ones devoid of any transaction history. Before Lelantus, Firo was the pioneering cryptocurrency to develop and deploy a functional implementation of the Zerocoin protocol. This protocol gained widespread adoption as one of the leading privacy protocols until it was superseded by Sigma and subsequently Lelantus due to cryptographic vulnerabilities uncovered in the Zerocoin protocol in 2019.