Crypto Preps for Looming Q-Day Predicted by Google

On the upside, advanced quantum computers could crack that 12-word seed phrase from 2013 that was scribbled on a piece of paper your mom threw out. But that level of encrypting ability can also unravel cryptocurrency’s core security … womp womp. 

Q-Day is the Y2K-esque time when quantum computers become advanced enough to decode all cryptography. Google recently warned it could be coming for cryptocurrency before the decade’s out. In a new paper, researchers wrote that quantum computers would need fewer than 500,000 physical qubits to break through bitcoin and other cryptocurrencies — 20 times fewer than previous estimates. 

Google researchers noted that 6.9 million public bitcoin keys are already exposed, leaving them wide open for quantum computers to crack at their leisure. There’s also a ~10-minute window when public keys are exposed during transactions, and the researchers said advanced quantum computers will be able to wheedle out a private key from a public one in nine to 12 minutes. 

Quantum Safety 101

Google is pushing companies to transition to post-quantum cryptography, which uses algorithms that quantum computers can’t easily crack. In PQC, a quantum computer may have to try to solve for, for instance, a vector in a thousand-dimensional lattice.

Developers are debating how to push crypto toward quantum-proof practices:

• The Bitcoin Improvement Proposal (BIP)-360 aims to provide a way for bitcoin owners with older wallets to opt in to move their holdings to safer addresses. Another idea, the Hourglass proposal, would restrict how quickly older coins can be spent to slow down any Q-Day mass liquidation events. But bitcoin has no central authority, and making changes on this scale is not just difficult but, in some ways, against the crypto’s core ethos.
• The No. 2 crypto by market cap, Ethereum, operates a little differently from bitcoin since its cofounder has remained an active figure developers listen to (no offense, Satoshi). Vitalik Buterin has proposed a roadmap for the crypto’s post-quantum transition with one change that could be rolled out in Ethereum’s next scheduled upgrade this year. 

It’s Always Tomorrow: There’s a running joke that quantum computing has been right around the corner since the 1980s, and the crypto industry’s divided about how imminent the threat really is. But more major figures seem to be taking it more seriously, as IBM and Google both aim to build practical quantum computers by 2029. Coinbase CEO Brian Armstrong said last week in response to Google’s paper that “we all need to solve it sooner rather than later.”