Coinbase’s head of research has warned that advances in quantum computing could pose broader risks to Bitcoin than simple wallet theft.
Future quantum machines could be able to break the cryptographic signatures that secure transactions, giving quantum-powered miners a significant speed advantage, said David Duong, the company’s global head of investment research. These two separate threats will impact both user funds and Bitcoin’s economic model.
Quantum risk goes beyond keys
Duong said that about a third of Bitcoin’s supply could be structurally exposed, as Bitcoin’s public keys are already visible on the blockchain. This number is close to 33%, or about 6.51 million BTC, and is held in an address type where the public key is publicly available and, in theory, a sufficiently powerful quantum computer could derive the private key. The report highlights that address reuse and outdated wallet formats are the main causes of this breach.
Experts say there are two main technological threats
One of the threats is signatures. Quantum algorithms like Shor can recover private keys from public keys at scale, allowing attackers to sign transactions and exfiltrate funds.
The second is the potential for mining issues. Fast enough quantum miners could find proof of work much faster than traditional rigs, disrupting incentives and block production. Duong et al. stress that the risk of signatures is theoretically short-lived, as it only requires cracking the signature associated with the exposed public key.
what the industry is doing
According to the report, word has already reached fund managers and standards bodies. Some institutional filings are starting to flag quantum risks, and NIST and other organizations are pushing for post-quantum cryptography efforts for a broader range of systems.
BTCUSD trading at $92,010 on the 24-hour chart: TradingView
Engineers in the cryptocurrency field are considering a migration path to replace it with a quantum-resistant scheme, but such changes to Bitcoin would be complex and would require widespread consensus.
Long-term problems, not immediate problems
Duong and other commentators say today’s quantum machines are too small and too noisy to crack Bitcoin’s code. This warning is about a possible point in the future, called “Q-day,” when a sufficiently large and stable machine will be able to run Scholl and related algorithms at scale. Schedules vary widely between professionals. Some predict it will take decades, while others say inequality is closing faster than many expected.
According to industry insiders, if a properly designed quantum machine is in place, coins remaining in addresses that have already tolerated public key vulnerabilities will be most at risk. This makes best practices such as avoiding address reuse and moving new balances to quantum-resistant addresses once old balances are available a prudent step. But experts say there is no easy solution that can fix the entire ecosystem in one click.
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