Zk-SNARK (Zero-Knowledge Succinct Non-Interactive Argument of Knowledge) is a cryptographic tool that enables one party to prove the authenticity of a statement to another party without revealing any information beyond the validity of the statement itself. This concept is called zero-knowledge proof and it's used to build privacy-focused systems.In the context of cryptocurrency, Zk-SNARKs are used to allow for private transactions on public blockchains. They allow for the validation of a transaction without revealing the details of the transaction, such as the amount and the addresses involved. This can increase the privacy and security of transactions on a public blockchain, as it allows users to keep their financial information private while still having the security of a decentralized, public ledger.The first use of Zk-SNARKs was in the Zerocoin protocol in 2013, which aimed to provide privacy for Bitcoin transactions. Later, the Zcash cryptocurrency, which was launched in 2016, implemented Zk-SNARKs as a privacy feature for its transactions. Since then, other cryptocurrencies have also implemented Zk-SNARKs, including Zcoin and Ethereum.In summary, Zk-SNARK is a zero-knowledge proof tool that allows for private transactions on public blockchains. The technology has a history of being used in privacy-focused cryptocurrencies to increase privacy and security of transactions.
