ZCash is based on Bitcoin, but the users have the option to encrypt the details of their transactions. That means that the senders and the receivers address as well as the amount can be obscured. ZCash states that they added privacy: „Zcash uses advanced cryptographic techniques, namely zero-knowledge proofs, to guarantee the validity of transactions without revealing additional information about them.“
ZCash is combining the four properties of blockchain and encryption: Immutability, single source of truth, privacy, selective disclosure. The genesis block has been mined on the 28th of October 2016.