Zcash plans post-quantum signatures and private per-swap keys

Zcash's quantum-resistance push now covers its cross-chain swaps. The Zakura team, which builds the newer software that runs the Zcash network, wants to give every ZEC swap through NEAR Intents its own separate viewing key, so a refund address posted on NEAR's public chain can't be worked backward by a future quantum computer to expose a user's wider payment history.

• NEAR Intents posts a user's Zcash refund address on its public chain for each swap; the address derives from the wallet's viewing key using elliptic-curve math that a large-enough quantum machine running Shor's algorithm could reverse.
• Spending keys stay with the user's main account, so cracking a swap key reveals only that one swap's payments; wallets would locate refunds via a database queried with private information retrieval (PIR), hiding which addresses they check.
• Zakura says open-source wallets such as Vizor could adopt the feature within weeks — ahead of the January target for quantum-resistant, hash-based signature opcodes, which initially target transparent payments (about seven in 10 issued ZEC).

The plans follow researcher Justin Drake's "bunker mode" warning and Google's Willow chip progress; ZEC fell about 11% on the week after the earlier January-target announcement. Read the full report.