1inch (@1inch): Quantum computers won't need to steal your data. It's been public since your first transaction.

Quantum computers won't need to steal your data. It's been public since your first transaction. Every time you send a transaction on a public blockchain, your public key becomes permanently visible on-chain. That’s by design – it’s how the system verifies ownership. The standard narrative around quantum computing and crypto goes like this: somewhere in the future, powerful enough quantum computers will break public-key cryptography and compromise wallets. A future problem. Something to prepare for eventually. The data needed to derive private keys from public keys – with a sufficiently powerful quantum computer – is already sitting on-chain. Permanently. For every wallet that has ever made a transaction. Unlike traditional harvest-now-decrypt-later scenarios, where attackers intercept encrypted communications today and decrypt them once quantum computers are powerful enough, blockchain requires no interception. The harvest happened the moment you sent your first transaction. What this means in practice Researchers at Google estimate a 10% chance that Q-Day – the point at which quantum computers can break modern public-key cryptography – arrives by 2032. Nature reported in April 2026 that recent advances represent “imminent risk” to cybersecurity infrastructure. Google and Caltech research suggests the cost of breaking traditional encryption is dropping faster than previously expected. The timeline remains contested – the direction of travel less so. Dormant wallets with large balances and publicly exposed keys are the most cited vulnerability. But any wallet that has ever signed a transaction on a public chain has left the same fingerprint. Why DeFi is better positioned than it looks The composability that makes DeFi vulnerable in a post-quantum scenario – cascading failures across liquidity pools, lending markets and bridges – is the same property that makes coordinated upgrades possible. Blockchain protocols can hard fork. They can upgrade cryptographic standards through governance. Traditional financial infrastructure cannot move at the same speed. Post-quantum cryptography already exists. Migration discussions are already happening across major blockchain ecosystems. Migration discussions are already happening – the bottleneck is coordination, not technology. A different way to read the timeline Quantum computing isn’t a future threat to crypto. It’s a current race between the maturation of quantum hardware and the migration of blockchain infrastructure to quantum-resistant cryptography. The data is already on-chain. Quantum hardware is getting cheaper faster than expected. Those two facts on a collision course is what the preparation window is actually about.