ZCash (ZEC)
ZCash (ZEC) is the only major cryptocurrency implementing zk-SNARKs (zero-knowledge succinct non-interactive arguments of knowledge) at the protocol level, providing shielded transactions whose sender, recipient, and amount are cryptographically hidden from all observers, including the ZCash blockchain itself. The theoretical privacy guarantees of ZCash shielded transactions exceed those of Monero's ring signatures in specific adversarial models. This guide covers using ZCash's shielded pool correctly to realise its full privacy potential, with links to academic resources and open-source tools.
How to Use ZCash Shielded Transactions Correctly
The critical distinction in ZCash is between transparent transactions (t-addresses) and shielded transactions (z-addresses, also called sapling or orchard addresses). Transparent transactions are fully visible on the ZCash blockchain — effectively identical to Bitcoin in privacy properties. Shielded transactions are cryptographically private: no third party can determine the sender, recipient, or amount. Using ZCash privately requires exclusively using z-addresses and ensuring all transactions are shielded.
The Zcashd full node wallet (z.cash/downloads) supports fully shielded transactions using the Orchard protocol (the most recent shielded pool, activated in Network Upgrade 5). The Zingo wallet (zingolabs.org) provides a user-friendly lightweight wallet with full Orchard shielded support and Tor integration. The Electric Coin Company's documentation at zcash.readthedocs.io covers the technical implementation of shielded addresses.
Critical privacy pitfall: many ZCash exchanges and services require t-addresses for deposits and withdrawals, creating a transparent on-chain record of funds entering or leaving your shielded pool. The best practice is to acquire ZEC through a peer-to-peer no-KYC platform, receive directly to a z-address, and transact exclusively between z-addresses thereafter. Any round-trip through a t-address breaks the shielded privacy chain.
What Are ZCash's Practical Privacy Limitations?
Despite its strong theoretical guarantees, ZCash's practical privacy is limited by the small shielded pool size. Historical data shows that a minority of ZCash transactions use shielded addresses, meaning the practical anonymity set — the number of shielded transactions that any given transaction is hidden among — is smaller than Monero's full-network anonymity set. Researchers at the Zcash Community Forum have documented that the shielded pool has grown since Network Upgrade 5, but the gap with Monero's mandatory-privacy model persists.
A second limitation is the "viewing key" architecture: ZCash shielded transactions can be made selectively transparent by sharing a viewing key with a trusted party (for regulatory compliance, for example). While this is a feature for some use cases, it means that ZCash's privacy is not entirely unconditional — it depends on the operator not sharing viewing keys with adversaries. Monero's design has no equivalent selective-transparency mechanism, making it unconditionally private. For comprehensive comparison, the cryptocurrency guide covers all major privacy models side by side.