Zcash Protocol Deep Dive: The Cryptography Behind Financial Privacy
Abstract Zcash represents one of the most sophisticated implementations of cryptographic privacy in production blockchain systems. Built on the theoretical foundations of the Zerocash protocol, Zcash employs zero-knowledge succinct non-interactive arguments of knowledge (zk-SNARKs) to enable fully private transactions while maintaining the integrity guarantees of a public ledger. This technical deep dive examines the Zcash protocol specification (Version 2025.6.1), covering its cryptographic primitives, privacy architecture, zero-knowledge proof systems, and the evolution from Sprout through Sapling to Orchard. We analyze the mathematical foundations, security properties, and design decisions that make Zcash a reference implementation for blockchain privacy. ...