Investors are increasingly expressing concern about quantum computers' ability to undermine current cryptocurrency cryptography. Castle Island Ventures partner Nick Carter explicitly stated that the developer community generally either ignores this threat or considers it too distant, while investors are paying growing attention.
What Is the Quantum Threat to Cryptocurrencies?
The quantum threat refers to the risk that quantum computers will effectively recover private keys from known public keys, thereby compromising transaction signatures. According to Carter, this threatens the integrity of systems whose security relies on current classical algorithms and could consequently alter trust in the cryptocurrency market.
Carter was also prompted to publish a detailed essay calling for preparations for the so-called Quantum Day (Q-day)—the moment when quantum computing reaches a level sufficient to pose a real risk. Various estimates circulate in this discussion, but the very fact of growing concern has become more noticeable across the industry.
Why Has the Quantum Threat Become Relevant in 2025?
According to Carter, 2025 marked a record year for quantum computing: startups raised at least $6 billion in investments, and individual companies like PsiQuantum secured $1 billion for large-scale projects. These inflows accelerate development pace and provide grounds for serious discussions about cryptography's future.
Besides private investments, government mandates play a crucial role: the U.S. National Institute of Standards and Technology (NIST) has called for abandoning algorithms vulnerable to quantum attacks by 2030 and fully discontinuing their use by 2035. The European Union and the United Kingdom follow similar timelines, increasing pressure to transition to new standards.
Specific Risks for Bitcoin
The primary technical risk is the possibility of deriving a private key from a public key, which could allow theft of funds from addresses with known public keys. Currently, public keys for approximately 6.7 million bitcoins worth about $604 billion are openly available, making this area potentially vulnerable if breakthroughs in quantum cryptanalysis occur.
Additionally, there is a theoretical risk of intercepting transactions within the brief window between their broadcast and inclusion in a block. A separate concern involves "lost" coins, including 1.7 million BTC attributed to Satoshi Nakamoto and early miners; these are stored on older address types and cannot be quickly moved by their owners, raising further questions about attack consequences.
Why Is the Community Slow to Defend Against Quantum Attacks?
Transitioning Bitcoin to quantum-resistant cryptography requires a complex soft fork and mass migration of users to new address types, which is technically and organizationally challenging. Estimates in the discussed material suggest the entire process—from discussions to full migration—could take up to ten years, making planning and coordination critical tasks.
Beyond technical difficulties, Bitcoin's development culture is traditionally cautious and conservative, so protocol changes proceed slowly and carefully. As a result, the most notable improvement proposals currently come not from recognized leaders but from lesser-known specialists, further slowing decision-making.
Expert Opinions on the Quantum Threat
Risk assessments vary: Capriole's CEO suggested the quantum threat could crash Bitcoin's price to $50,000, while other industry figures provide more distant timelines or downplay the likelihood of imminent breaches. These differences reflect uncertainty both in quantum technology's development pace and its practical threat to blockchains.
Adam Back, CEO of Blockstream, believes Carter exaggerates the issue: in his view, computers capable of breaking Bitcoin's cryptography will appear in 20–40 years or may never reach the required level. This range of estimates shows the debate remains open and requires technical preparation.
Why This Matters
For miners, it is important to understand that the threat affects not only large holders but also the security of addresses and transactions across the network. If Q-day arrives before migration completes, it could trigger market panic, widespread losses, or significant price shocks.
Even if the risk seems remote now, millions of bitcoins with exposed public keys and substantial investments in quantum technologies make this topic relevant for miners' key and address management decisions. Given conflicting expert timelines, considering all viewpoints is crucial for planning.
What Should Be Done?
Miners with any number of devices should already minimize address reuse and adopt practices that reduce public key exposure. This will lower the risk that your funds become vulnerable if effective quantum hacking methods emerge.
- Do not reuse addresses and, when possible, transfer funds to new addresses after spending.
- Follow official announcements from developers and NIST regarding standards and migration schedules.
- Avoid storing large amounts on addresses with known public keys; if necessary, distribute funds across multiple wallets.
- Prepare contingency plans for a soft fork: verify software and wallet compatibility with proposed updates.
These steps do not guarantee full protection against long-term scenarios but reduce your current exposure and ease potential mass migration in the future. It is important to act systematically and not wait for a critical situation.
Additional Materials
For a detailed risk analysis, see the quantum threat to Bitcoin article, which describes technical attack scenarios and their blockchain consequences. Also useful is the article on quantum computing's possible impact on Bitcoin's price and related risks, including the $50,000 price drop estimate — price drop to $50,000.
