Plain meaning
Start with the shortest useful explanation before going deeper.
A privacy-focused cryptocurrency launched in October 2016 that pioneered the use of zk-SNARKs to enable fully shielded transactions where sender, receiver, and amount are cryptographically hidden on a public blockchain. Zcash uses a UTXO model derived from Bitcoin and maintains multiple value pools (transparent, Sapling, Orchard) with a turnstile mechanism ensuring supply integrity. Major upgrades include Sapling (2018) for efficient proofs and NU5/Orchard (2022) introducing Halo 2 to eliminate trusted setup.