Zcash weighs freezing its oldest shielded pool as developers move to cut quantum exposure in cross-chain swaps

Zcash is about to set a precedent that other chains will study. Its next hard fork, Network Upgrade 7 (NU7), would stop accepting the older transaction format needed to spend from the Sprout shielded pool. This is the change specified in Zcash Improvement Proposal (ZIP) 2003. Any ZEC still in Sprout when the upgrade activates would stay issued but could not be moved, even by a holder whose private keys are intact.

Sprout launched with Zcash in 2016 and was later closed to new deposits. It still holds roughly 23,000 ZEC. The proposal does not burn those coins. It leaves open a future route to restore access, but it also warns holders that they may never be able to spend funds left behind. NU7 went live on testnet on Oct. 6, and developers plan to decide on Oct. 20 whether to proceed with mainnet activation on Nov. 5. CryptoSlate reports that the mainnet decision remains pending.

The second change addresses a privacy gap at the point where Zcash connects to other chains. Zakura, the team that builds a Zcash client, wants every swap routed through NEAR Intents to get its own key. NEAR Intents is a cross-chain routing service in which users state a trade and third parties carry it out. Today a swap can leave a Zcash refund address on NEAR's public ledger. CoinDesk reports that a sufficiently capable quantum computer could later use that address to expose the user's wider payment history. Shielded Zcash transactions hide amounts and counterparties, but the addresses that touch transparent chains stay public permanently. The team treats this exposure as urgent because those addresses are already being recorded and cannot later be hidden.

NEAR Intents already has a record of security failures. On Oct. 1 the service lost about $3.8 million, mostly in Tether, from a treasury contract on BNB Chain after a bug in how its deposit-and-withdrawal infrastructure communicated with its smart contracts. It paused services, patched the flaw and pledged to reimburse users, and Rekt News documented the incident. Zcash's growing reliance on this route for swaps therefore adds custody and privacy dependencies outside Zcash's own consensus.

Both changes belong to a longer program. Zcash developers have said they aim to make the network quantum-resistant by 2027. The Sprout decision is the first time that program forces a choice about coins whose owners may not be paying attention.