Zcash’s Transparent-Wallet Plan: Address Rotation, Private Queries and Unfinished Signature Migration
A transparent blockchain address can reveal more about its owner after the first spend than before it. Zcash developer Zakura wants wallets to rotate transparent addresses without giving a wallet synchronization server an easy way to link those addresses together. Its engineering explanation, revisited in October 11 reporting, also sketches a future hash-based signing option. The distinction between these pieces is important. Zakura describes an experimental private-query function in its Vizor wallet and a planned January arrival for post-quantum signature opcodes. It has not announced that Zcash mainnet has universally adopted a new quantum-safe transaction signature system.The security issue begins when a public key is exposed A conventional transparent Zcash address contains a hash derived from a public key. Merely displaying that address does not necessarily reveal the full public key. But spending from the address can publish the public key as part of signature verification. If some future cryptanalytic advance made the relevant elliptic-curve problem tractable, already-exposed public keys would be a different category of risk from previously undisclosed ones. Rotating to a new derived address after a transaction limits reuse of the same exposed key. One seed phrase can generate multiple distinct addresses, so rotation does not ordinarily require maintaining a
