- Zakura has suggested using separate viewing keys for ZEC swaps via NEAR Intents to reduce the risk of exposure from future quantum attacks.
- The concept is designed to stop compromised viewing keys from revealing an entire Zcash payment history, which includes private memos and amounts.
- To help wallets locate refunds without exposing checked addresses to database operators, Zakura implements private information retrieval (PIR).
Zcash infrastructure builder Zakura has introduced a wallet feature concept meant to shield user transaction privacy from prospective future quantum computing threats. By assigning a distinct incoming viewing key to each Zcash (ZEC) swap executed via NEAR Intents, the solution restricts the amount of payment history an attacker could uncover if they manage to break the cryptographic security of a publicly visible address.
Adam Tucker, a Zakura developer, detailed the proposal on October 18. It addresses a vulnerability inherent to cross-chain swaps: NEAR Intents displays Zcash addresses on its public blockchain so that any unused funds can go back to the user if a transaction fails or does not use the entire deposit. These addresses stay visible even when refunds are unnecessary.
While Zcash shielded transactions effectively conceal transaction details, addresses belonging to a single wallet generally share a common incoming viewing key. A sufficiently advanced quantum computer utilizing Shor’s algorithm could conceivably extract that key from an exposed address, potentially exposing the values and private memos of any payments received by that account. At present, no quantum computer capable of executing such an attack has been successfully demonstrated.
Separate Keys Aim to Limit Potential Exposure
According to Zakura’s blueprint, every swap would utilize its own incoming viewing key while leaving the wallet’s existing spending key untouched. Should a future attacker manage to recover the viewing key tied to a single publicly exposed address, the resulting data leak would restrict itself strictly to payments associated with that specific address, leaving the broader transaction history of the wallet safe.
This architecture also tackles the operational hurdle of restoring wallets that contain numerous separate keys. To solve this, Zakura suggests employing private information retrieval (PIR), a cryptographic method that lets a wallet scan a database for pertinent transactions without disclosing the specific addresses it is querying to the database operator.
Implementing this modification does not necessitate any upgrades to the Zcash network. Zakura notes that software wallets utilizing its open-source libraries, such as Vizor, could adopt this capability over the next few weeks. Support for hardware wallets is anticipated at a later date once the necessary compatible firmware is released.
This initiative coincides with ongoing efforts by Zcash developers toward comprehensive quantum-resistant payment safeguards, such as the upcoming Tachyon upgrade. Even so, Zakura’s architecture functions purely as a wallet-level precaution rather than an already active network-wide remedy.
The primary objective is to minimize the volume of confidential transaction data that could be exposed during a hypothetical quantum assault down the road. Furthermore, the framework permits users to keep utilizing their current wallet accounts to spend funds normally.
Frequently Asked Questions
What is the main goal of Zakura’s proposal?
The main objective is to protect Zcash transaction privacy against theoretical future quantum computing attacks by limiting the potential payment history exposed during cross-chain swaps.
Does this require a Zcash network upgrade?
No, the proposal is a wallet-level safeguard and does not require an upgrade to the Zcash network.
How does Zakura protect wallet restoration privacy?
It uses private information retrieval (PIR), enabling wallets to search a database for relevant transactions without revealing the checked addresses to the database operator.
When will this feature become available?
Software wallets built using Zakura’s open-source libraries, including Vizor, could integrate the feature in the coming weeks, while hardware-wallet support will follow later once compatible firmware is ready.
