Zcash, which name originates from Zerocash, is the first open, permissionless cryptocurrency that can fully protect the privacy of transactions using zero-knowledge cryptography. To compare, Bitcoin and most cryptocurrencies expose your entire payment history to the public. The Zcash’s improvement over Bitcoin is the addition of privacy.
What is so special about ZEC? It is a decentralized and open-source cryptocurrency that provides strong privacy protections and selective transparency of transactions. Thanks to encryption technology such as zk-SNARK, shielded transactions are possible to hide the sender, recipient, and value on the blockchain. Zcash payments are still published on a public blockchain but those details remain private.
ZEC is based on peer-reviewed cryptographic research, and built by a security-specialized engineering team on an open source platform based on Bitcoin Core's battle-tested codebase.
Zcash uses advanced cryptographic techniques, namely zero-knowledge proofs, to guarantee the validity of transactions without revealing additional information about them. The payment information is encrypted so the protocol uses a novel cryptographic method to verify their validity.
Whole amount of tokens which will be issued is limited to 21 millions, just like in the case of Bitcoin. The creators of ZEC claim that if Bitcoin is like http for money, Zcash is https - a secure transport layer.