Firo (FIRO), originally known as Zcoin (XZC), is an open-source privacy-focused cryptocurrency token that launched in Sep 2016. To enable privacy, Firo uses zero-knowledge proofs via the Zerocoin protocol. Firo is a cryptocurrency originally proposed by Johns Hopkins University professor Matthew D. Green and graduate students Ian Miers and Christina Garman as an extension to the Bitcoin protocol that would add cryptographic anonymity to Bitcoin transactions. With Firo, only the sender and receive would be able to ascertain the exchange of funds in a given transaction, as no transaction histories are linked to the actual coins. Firo operates a multi-node model where mining nodes verify blockchain transactions. The name change from Zcoin to Firo occurred in November 2020.