A proof-of-work (PoW) digital currency using the Lyra2 hashing algorithm, Zcoin aims to guarantee real financial autonomy. The sigma protocol makes private financial transactions possible. To solve the problem of double spending, it stores transactions on a public ledger known as a blockchain. Thanks to the zero-knowledge proofs, you can own a Zcoin coin without revealing the coin you own. Recently, a typographic bug was discovered in the Zcoin protocol, which cost the network almost $400,000. However, it did not compromise Zcoin’s anonymity features.