Zcash Developers Unveil Plan to Shield Keys From AI and Quantum Attacks
Key Takeaways
- •Zakura expects post-quantum signature opcodes to arrive in Zcash in January, enabling hash-based signatures for the network's transparent payments.
- •The plan combines address rotation after every transaction with the Winternitz one-time signature to avoid the elliptic-curve math researchers fear AI or quantum computers could crack.
- •Private information retrieval, a feature rolling out this week in the Vizor wallet, lets wallets check balances across rotating addresses without servers linking them to the same user.
- •The proposal follows warnings from Justin Drake and Vitalik Buterin that AI-driven mathematical advances could break ECDSA signatures, potentially within months to two years.
- •The Zakura plan applies only to Zcash's transparent payments, and no date has been confirmed for network-wide activation of the opcodes.

A team of Zcash developers says it already has an answer to the “bunker mode” debate preoccupying crypto: a concrete plan to protect users' keys from AI- and quantum-powered attacks.
Zakura, which builds a Zcash full node, said its team expects post-quantum signature opcodes to land in Zcash in January, enabling hash-based signatures for the network's transparent payments. Opcodes are low-level instructions that would let the network verify a new type of signature. The goal, according to an engineering post by Roman Akhtariev, is “full post-quantum safe transparent pools with hash based signatures.” If the January timing holds, transparent payments would gain a route to signatures that don't depend on the elliptic-curve math at the center of the current debate.
The approach pairs address rotation with private information retrieval, a feature arriving this week in the Vizor wallet so servers can't link a user's addresses. It follows Ethereum researcher Justin Drake's “bunker mode” warning. The plan covers only transparent payments, and no network activation date has been confirmed.
Zcash supports two kinds of payments: shielded ones that hide the sender, recipient and amount, and transparent ones that are publicly visible, much as they are on Bitcoin. A transparent address contains a hash of a public key, which stays hidden until the owner spends from it and reveals the key onchain.
On October 8, Zakura laid out its proposal in a post on X:
Here's our plan for quantum-safe, unlinkable, rotating taddrs. Possible with Zcash, today. While others are worrying about the viability of rotating transparent addresses, we're already solving linkability.
— Zakura (@ZakuraZcash) October 8, 2026
Zakura's approach combines two defenses. Wallets would rotate to a fresh address after every transaction, keeping public keys out of view, and add a hash-based backup signature known as WOTS, short for the Winternitz one-time signature. Hash-based schemes avoid the elliptic-curve math that researchers fear AI or quantum computers could eventually crack.
Rotation creates a privacy problem, though. When a wallet asks a server to check balances across many addresses, the server can tell they belong to the same user. Zakura says it addresses that with private information retrieval, or PIR, a cryptographic technique that lets a wallet fetch records without revealing which ones it's requesting. The feature is rolling out this week in the Vizor wallet, where users can already test it by toggling “private queries” in the settings.
“While others are worrying about the viability of rotating transparent addresses, we're already solving linkability,” Zakura wrote on X.
That's a nod to Ethereum Foundation researcher Justin Drake, who this week urged holders to calmly move funds to fresh addresses. The public response to Drake's call to action, however, was not so calm.
Drake warned that AI-driven math could break the ECDSA signatures securing Bitcoin and Ethereum before quantum computers do, “in the worst case in months not years.” Ethereum co-founder Vitalik Buterin has since weighed in on the debate and said he believed it was “plausible” that AI-driven advancements in math could break encryption within the next two years.
The Zakura plan covers only Zcash's transparent side, and the post didn't say how or when the opcodes would be activated across the network. The next checkpoints are the January opcode rollout and any activation proposal that would carry the change to the network as a whole.
The push comes as Zcash draws growing institutional interest, including another proposed U.S. ETF tied to the Winklevoss twins and Europe's first Zcash ETP. It also follows an upgrade designed to make private payments three times faster.