Zcash developer proposes quantum-resistant privacy for NEAR swaps

The core of the issue lies in how cross-chain services like NEAR Intents interact with the Zcash network. When users swap assets, refund addresses are often recorded on the public NEAR blockchain. While current hardware cannot reverse the underlying elliptic-curve cryptography, developers warn that future quantum computers running Shor’s algorithm could theoretically recover viewing keys from these exposed addresses. This would allow an attacker to deanonymize shielded transaction amounts and private memos.

Zakura’s solution introduces a one-time incoming viewing key for each swap, derived from existing account credentials. Because this process only affects the viewing mechanism, the user’s primary spending key remains unchanged and fully functional. This design avoids the cumbersome requirement of creating separate accounts for every transaction, a practice that currently complicates management for hardware wallet users. To manage the increased complexity of wallet recovery, the proposal incorporates private information retrieval (PIR), allowing users to locate their transactions without disclosing specific addresses to database operators.

Integration is expected to begin in the coming weeks for software wallets such as Vizor, which utilize Zakura’s open-source libraries. Hardware wallet support remains a secondary priority, contingent on firmware updates to accommodate the new key derivation process. This initiative runs parallel to broader industry efforts, including the anticipated 2027 rollout of post-quantum signature instructions for the Zcash network, aimed at securing spending authorizations against long-term cryptographic risks.