zk-SNARK

zk-SNARK (Zero-Knowledge Succinct Non-Interactive Argument of Knowledge) is a cryptographic proof system that allows one party to prove possession of certain information, such as a secret key, to another without revealing that information and without any interaction between them. It is used in various cryptocurrencies such as Zcash, where it is used to prove that transactions are valid without revealing any identifying information about the sender, recipient or the transaction amount. This technology is important because it allows for increased privacy, security and decentralization in blockchain-based systems.