Zcash software developer Zakura has proposed a wallet change that would assign a separate viewing key to each ZEC swap through NEAR Intents. The plan addresses the possibility that future quantum computers could expose past payments through Zcash addresses stored on a public blockchain. The feature remains under development, with no confirmed launch date.
NEAR Intents lets users exchange assets between blockchains. When a customer swaps shielded ZEC for USDC, the service records a Zcash refund address on NEAR's public blockchain. That address remains visible even when the exchange succeeds and no refund takes place. The same exposure occurs when users swap into ZEC, because the service publishes their receiving address.
Zcash wallets can generate many shielded addresses, but addresses within the same account normally share an incoming viewing key. That key helps a wallet find and read incoming payments, including amounts and private memos. In an engineering post, developer Adam Tucker warned that a future attacker could use one published address to connect payments across the account.
This scenario requires a quantum computer powerful enough to recover the key from public address data. No machine capable of carrying out that attack has been publicly demonstrated. Moreover, a viewing key alone cannot authorize transfers of ZEC.
Zakura's design creates a fresh incoming viewing key for every swap while keeping the account's spending key unchanged. As a result, someone who recovered one swap's viewing key would only gain access to payments associated with that address, according to the proposal.
The wallet would generate each key from existing account information and a numbered swap record. It would also store an encrypted note identifying the refund address used. This would help users recover returned ZEC without maintaining a separate account for every exchange.
The team rejected the separate-account approach because it could complicate hardware wallet use. Some devices restrict which accounts can sign transactions, while others require additional approvals to spend across accounts. Zakura's method aims to avoid those limits.
Using a different key for every swap introduces another problem. A wallet restored from a backup might need to search years of transactions with hundreds of keys, increasing the time needed to find funds.
To address that, Zakura proposes private information retrieval, a method that lets a wallet question a database without showing the operator which address it is checking. The wallet would download address filters, identify possible matches and request the relevant transaction records privately.
For incoming ZEC swaps, the wallet would check generated addresses in sequence. It would stop after finding 30 consecutive addresses that NEAR had neither used nor received in a swap request. The team says this process would also prevent abandoned swap quotes from causing address reuse.
The proposal forms part of wider work on Zcash's future security. Previous reporting on Zcash's January quantum plans described a target of January 2027 for new signature instructions. Those instructions concern spending security, rather than the visibility of historical shielded payments.
Separately, July's Ironwood network upgrade introduced other network protections. Cross-chain demand is also evident in earlier Aurora Intents swaps, which processed more than $19 million during September's zkSNARKS auction.
Zakura says wallets using its libraries, including Vizor, could add the proposed feature “in the coming weeks.” Hardware wallet support depends on future firmware changes. Neither timetable represents a confirmed release.
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