Zcash is a proof-of-work (PoW) cryptocurrency designed to address some of Bitcoin''s inherent flaws, such as the lack of substitutability. Moreover, Zcash relies on a set of zero-knowledge proofs called zk-SNARK to improve anonymity and thus substitutability. In the Zcash network, addresses can be either private ("z-addresses") or transparent/public addresses ("t-addresses"). Both types of addresses are interoperable. Some of the key features include low-fee transactions, cryptographic memos (allowing the sender to disclose relevant information to the recipient), payment disclosure (allowing transaction-specific details to be disclosed to multiple third parties), multi-signature transactions and transaction expiration (if not mined, the transaction will expire after a specific number of blocks), according to its team. Originally built on the Zerocash protocol, Zcash has been relying on Sapling - i.e., part of its own continuous improvement strategy - since late 2018.Sapling has enabled efficiency improvements in blocking transactions (reduced memory requirements), decoupled sending privileges (e.g., zero-knowledge proof of hardware independent of the hardware used to sign transactions) and enabled important system improvements (thus enabling blocked addresses to view details of transactions to and from without compromising their private keys)