How Zcash Plans to Hide Your Keys From AI and Quantum Attacks

What it is

Zakura, a Zcash full-node developer, has published a plan for quantum- and AI-resistant transparent (t-addr) payments. Zakura expects post-quantum signature opcodes in Zcash in January. Roman Akhtariev's engineering post describes the goal as "full post-quantum safe transparent pools with hash based signatures."

How it works

A transparent address holds a hash of a public key. The key stays hidden until the owner spends and reveals it onchain. The plan relies on two things:

• Rotation: the wallet moves to a fresh address after every transaction, so a key is never exposed on an address that still holds funds.
• WOTS backup: a hash-based signature scheme that avoids elliptic-curve math.

Rotation lets a server link a user's addresses when the wallet queries balances across many of them. Private information retrieval (PIR) addresses this by letting the wallet fetch records without revealing which ones it asked for.

flowchart LR
    A[Wallet rotates addresses] --> B{Balance lookup}
    B -->|Plain query| C[Server links addresses]
    B -->|PIR| D[Server learns nothing]

What to do

• Vizor wallet users can test PIR now. Toggle "private queries" in the wallet settings (rolling out this week, per the page).
• The page gives no migration steps for the opcodes or WOTS, since neither is live.

Caveats

• The plan covers only transparent payments.
• The page does not say how or when the opcodes would be activated across the network, and no activation date is confirmed. "January" is Zakura's own expectation.
• The threat framing is contested. Justin Drake warned that AI-driven math could break ECDSA "in the worst case in months not years." Vitalik Buterin called it "plausible" within two years. The page presents these as warnings, not demonstrated breaks.