Zcash was the first real-world application of zero-knowledge proofs, a novel method by which one party (the prover) can prove to another (the verifier) that a statement is true, without revealing any information beyond the validity of the statement itself — like, proving a person is over 21 years old without exposing their driver’s license information or revealing their birthdate. In Zcash, zero-knowlege proofs enable privacy. They ensure a person’s wallet balance and transaction history are accurate without revealing the actual balance and transaction history. So, if a person tries to send ZEC to someone else, for example, the Zcash blockchain network is assured that the ZEC being sent is authentic and that the sender’s balance will cover the transaction.