Zcash is a digital currency, or cryptocurrency, like Bitcoin. (In fact, Zcash was built on the original Bitcoin code base.) It was conceived by scientists at MIT, Johns Hopkins and other respected academic and scientific institutions.
Privacy is built into the core of Zcash, allowing people to send and receive Zcash without disclosing the sender, receiver or the amount transacted. Privacy allows good people to transact safely over digital mediums. Transparent addresses and transactions are also available.
White Paper / Documentation