Zcash team plans January upgrade for quantum resistant payments amid AI security concerns

Zcash developers target January for quantum resistant signatures and introduce private queries to protect transparent wallet lookups.

Zcash developers are targeting January for new signature protections designed to make transparent payments resistant to quantum attacks, according to an engineering post by Zakura’s Roman Akhtariev.

Akhtariev said the team plans to introduce new instructions for verifying hash based spending signatures in January. The post does not specify a confirmed network activation date.

The proposal also addresses a separate privacy problem. Wallets managing multiple transparent addresses can reveal which ones belong together when requesting balances and transaction histories from a server.

Zakura’s approach combines fresh addresses, hash based signatures and private information retrieval, or PIR. Each component addresses a different exposure.

Standard Zcash transparent addresses contain a hash of a public key. The key remains hidden until funds are spent from the address. Once disclosed, it continues to control any funds left there or received later.

Moving remaining funds to a fresh address places them behind another public key hash. Akhtariev argues that this offers additional protection if recovering private keys from exposed public keys becomes practical while hashes remain secure.

Wallets can generate these addresses from an existing seed phrase. Users do not need a separate wallet or backup for each address. However, sharing an extended public key can expose the public keys associated with multiple receiving and change addresses.

Address rotation also creates a practical challenge. A wallet still needs to monitor payments and recover its history, and ordinary server requests can link otherwise separate addresses to the same user.

PIR lets the wallet retrieve records without revealing which records it requested. Zakura’s design uses public activity filters that wallets check locally before making private lookups for relevant transaction histories.

The tool can also support recovery from a seed phrase and retrieve transaction details without submitting a transaction ID as a readable search term. Transparent transactions remain visible on the blockchain. The privacy protection applies to wallet queries.

Akhtariev said the transparent PIR component is coming to Vizor this week. An experimental deployment is already available through the wallet’s “Private queries” setting.

The proposal follows Ethereum researcher Justin Drake’s call for the industry to prepare for “bunker mode.” Drake warned that AI driven mathematical advances could threaten existing wallet signatures and urged a gradual move to addresses with unexposed public keys. 

Zakura’s January goal focuses on Zcash’s transparent pool. It does not establish quantum protection for the network’s shielded payments, which require separate safeguards.