Zcash
Zcash developers are outlining a strategy to strengthen the network’s transparent transactions against potential future threats from artificial intelligence-driven cryptanalysis and quantum computing. Zakura, a team developing a Zcash full node, expects post-quantum signature opcodes to be introduced into the network’s development process in January, potentially enabling hash-based signatures for transparent payments.
The proposed approach aims to reduce reliance on cryptographic methods that researchers believe could eventually become vulnerable to advances in computing. According to Zakura engineer Roman Akhtariev, the objective is to support post-quantum-secure transparent transaction pools using hash-based signatures. However, the announcement does not establish a confirmed network activation date, and the proposed changes should not be interpreted as already implemented across Zcash.
Zcash supports both shielded and transparent transactions. Shielded payments are designed to conceal transaction details, including the sender, recipient and amount, while transparent payments expose information publicly in a manner similar to Bitcoin. In the transparent system, an address contains a hash of a public key, which is revealed when the owner spends funds from that address.
Zakura’s proposal combines two mechanisms intended to improve security and reduce the ability to associate multiple addresses with the same user. The first involves rotating transparent addresses after transactions, limiting repeated use of the same address and helping keep public keys concealed until they are needed for spending. The second involves Winternitz One-Time Signatures, or WOTS, a hash-based signature scheme intended to provide an alternative to cryptographic approaches that could be threatened by sufficiently advanced quantum computers.
Address rotation, however, can introduce a separate privacy challenge. When wallets query servers to check balances across multiple addresses, those requests could reveal relationships between addresses and potentially allow the server to associate them with the same user. Zakura says it intends to address this issue through private information retrieval, a cryptographic technique that allows users to retrieve information without revealing precisely which records they are requesting.
The private-query feature is being introduced in the Vizor wallet, where users can test it through a setting labeled “private queries.” The combination of address rotation and private information retrieval is intended to make transparent addresses more difficult to link, while the proposed hash-based signatures would address a separate concern involving the long-term security of transaction authorization.
The initiative comes amid a broader debate over the potential threat that advances in artificial intelligence and quantum computing could pose to established cryptographic systems. Ethereum Foundation researcher Justin Drake has warned that rapid advances in mathematical capabilities could create risks for digital signatures, potentially encouraging users to move funds to fresh addresses. Ethereum co-founder Vitalik Buterin has also discussed the possibility that AI-driven advances could accelerate the development of techniques capable of breaking existing cryptographic protections.
These scenarios remain uncertain, and the timeline for any practical threat depends on developments that cannot yet be established with confidence. Nevertheless, the discussion has increased attention on post-quantum cryptography and the steps blockchain networks may need to take to protect assets over the long term.
Zakura’s proposal currently addresses only Zcash’s transparent transaction system. The development team has not specified when the proposed opcodes would be activated across the network, and the announcement does not establish that the approach will protect every type of Zcash transaction against all potential AI or quantum attacks.
The effort comes as Zcash attracts additional institutional interest, including proposals for exchange-traded investment products linked to the cryptocurrency in the United States and Europe. It also follows an upgrade aimed at improving the speed of shielded payments. Whether Zakura’s proposed safeguards become part of the live network will depend on further development, implementation and network-level activation.
