Every time someone swaps private ZEC through NEAR Intents, a small clue is left on a public blockchain. Today it is harmless. A big enough quantum computer could one day change that, so Zcash developers want to fix it now.
By Michal Beno, CEO, OneMiners19 October 2026
When you swap private ZEC for a token like USDC through NEAR Intents, one of your private Zcash addresses is posted on NEAR's public chain as a refund address. A future quantum computer could, in theory, work backwards from that address to the key that reveals your whole payment history. The team behind Zakura plans to give every swap its own key, so a cracked address would expose one swap and nothing else. Your funds are not at risk either way.
1 swap
the most a cracked key would reveal after the fix
0
quantum computers able to do this today
Weeks
until wallets such as Vizor could add it
$1,166
ZEC price on Monday
CoinDesk, 19 October 2026; CoinGecko, 19 October 2026.
Think of it as a return address
Imagine posting a sealed letter. Nobody can read what is inside, but you have written a return address on the back, just in case it cannot be delivered. That is roughly what happens with a NEAR Intents swap. The service posts one of your private Zcash addresses on NEAR's public chain so it can send back any unused ZEC. The address goes up when your deposit arrives, and it stays up even if the swap works perfectly.
Today that is fine. The maths that links an address to its key, elliptic-curve cryptography, cannot be reversed by any computer that exists. But Shor's algorithm, published in 1994, shows that a large enough quantum computer could do it.
Why one key can reveal so much
Zcash addresses are created from a wallet's viewing key, and one viewing key usually sits behind many addresses. So if someone cracked the key behind a single refund address, they could see every payment that wallet ever received, with amounts and memos. That is the part Zcash users care about.
What they could not do is spend the money. Zcash keeps spending keys separate from viewing keys, so funds stay safe. The risk is to privacy, not balances. Bitcoin has its own version of this debate: coins from Satoshi's era sit in addresses whose public keys are already on-chain, and Google said last week that its Willow quantum chip produced near-perfect versions of a building block such an attack would need.
The fix: a fresh key for every swap
One swap, one viewing key
Each NEAR Intents swap gets its own viewing key. Crack it, and you see that one swap only.
Spending stays put
The spending keys remain with the user's main account, exactly as before.
Solve the restore problem
Hundreds of swaps means hundreds of keys, and scanning the whole Zcash chain with each one after a restore would be slow.
Ask privately
So wallets query a database using private information retrieval (PIR): the wallet learns where its refunds landed, and the database never learns which addresses it asked about.
Before and after the change
Based on the Zakura team's engineering post, as reported by CoinDesk, 19 October 2026.
When does it arrive?
Zakura, a newer version of the software that runs the Zcash network, says wallets built on its open-source libraries, including Vizor, could add the feature within weeks. Hardware wallets would follow once their firmware supports it. That would put it ahead of the January target Zcash developers set earlier this month for quantum-resistant payments. A capable quantum computer is still likely years away, with no firm timeline, which is exactly why fixing it now is the calm, cheap option.
What it means for Zcash miners
Privacy is the whole reason people use Zcash, and every upgrade that protects it strengthens the case for the coin. Miners secure that network. At Monday's numbers, ZEC near $1,166 and the network at 31.4 GSol/s, an Antminer Z15 Pro 840K mines about 0.038 ZEC a day, worth about $45 before power, or about $42 after power at 4.8 cents per kWh.
Antminer Z15 Pro 840K at different ZEC prices
Net US dollars per day after power at 4.8 cents per kWh, today's network hashrate
Blockchair Zcash stats, 19 October 2026; miner reward 1.25 ZEC per 75-second block; before pool fees. Scenario only, not a forecast.
Antminer Z15 PRO - 860 KH/s
860 KSol/s, 2,849 W, about 3.3 J per KSol
View miner
Antminer Z15 PRO - 840 KH/s
840 KSol/s, 2,780 W, about 3.3 J per KSol
View miner
Zcash keeps investing in the thing that makes it different, and that is good news for anyone mining it. OneMiners hosts Zcash miners next to Bitcoin miners, from $0.048 per kWh and from $0.0364 per kWh on a 7-year prepaid contract. With a coin that can swing hard, a low, fixed power price is the steadiest part of the plan.
Frequently asked questions
Can a quantum computer steal Zcash?
Not through this issue. The refund-address risk is about privacy: a cracked viewing key could show payment history, but spending keys are separate.
What is NEAR Intents?
A cross-chain swap service. When you swap ZEC through it, a private Zcash refund address is posted on NEAR's public chain.
What is Zakura?
A newer version of the software that runs the Zcash network. Its team proposed the per-swap viewing key fix.
Does this change Zcash mining rewards?
No. It is a wallet-level privacy change. Mining rewards depend on the ZEC price and network hashrate.
Mine the privacy coin on a low, fixed power price.
See Zcash minersSee hosting locationsSOURCES AND DATA
- Zcash developers plan a fix to keep ZEC swaps private from future quantum computers: CoinDesk, 19 October 2026
- Zakura engineering post on quantum unlinkability, as reported by CoinDesk, 19 October 2026
- Shor's algorithm: Peter Shor, 1994
- Zcash network hashrate: Blockchair, 19 October 2026; ZEC price: CoinGecko, 19 October 2026
- Miner prices and specs: OneMiners catalogue, 14 October 2026
Michal Beno
CEO of OneMiners, the global Bitcoin mining hosting and hardware platform with 15 published hosting locations, 7-year fixed electricity contracts and a 7-year hardware warranty. He writes about the economics of industrial Bitcoin mining.
Informational only, not financial advice. Figures are a snapshot from public market data, news reports and the OneMiners catalogue as of 19 October 2026 and can change quickly. Net-per-day figures are at today's numbers, before pool fees, and are not a forecast. Crypto prices can fall as well as rise. No return is offered or implied. Do your own research.
