CoinShares, a major European digital asset manager, today released a detailed analysis arguing that the threat posed by quantum computing to Bitcoin’s security is significantly more limited than some recent estimates have suggested. The firm sharply pushed back on claims that up to 20 %–50 % of Bitcoin’s supply could be vulnerable, saying that only a tiny portion of coins — roughly 10,200 BTC — face any meaningful practical risk from future quantum attacks.
Key Findings from the CoinShares Report
- Limited Practical Exposure: According to CoinShares, about 1.6 million BTC — around 8 % of the total Bitcoin supply — are held in older legacy Pay-to-Public-Key (P2PK) addresses where public keys are visible on-chain. However, most of those coins are split into many smaller outputs, which even highly advanced quantum computers would take many centuries to exploit, the firm said. Only about 10,200 BTC are in large outputs that could realistically be targeted in a meaningful computation attack.
- Quantum Tech Still Far Off: Researchers and the report emphasized that quantum computers capable of cracking Bitcoin’s cryptographic signatures using algorithms like Shor’s are likely years to decades away. Estimates suggest machines would need orders of magnitude more qubits than today’s leading systems to break Bitcoin keys within feasible time frames, placing the practical threat well into the future.
- Modern Addresses Less Vulnerable: Most Bitcoin today is held in modern address types (such as Pay-to-Public-Key-Hash and Taproot), which only expose public keys briefly when coins are spent — greatly reducing exposure compared to legacy formats.
Countering Higher Vulnerability Estimates
The CoinShares analysis directly challenges previous concerns from other research groups and market commentators. Some studies have suggested a much larger portion of the Bitcoin supply could be at risk once quantum capabilities improve. CoinShares maintains such estimates often aggregate very different categories of address exposure without accounting for how Bitcoin’s script and address types influence practical vulnerability.
Financial institutions and analysts who have publicly worried about Bitcoin’s long-term security occasionally cite larger figures — including claims that up to one-third or more of Bitcoin’s circulating supply could be at risk due to public key exposure from address reuse and other factors. CoinShares’ findings counter those scenarios as overly pessimistic.
Market and Technical Context
In its report, CoinShares framed the quantum threat as a long-term engineering challenge rather than an immediate financial crisis. With current cryptographic techniques like elliptic curve digital signatures (ECDSA) and Schnorr, Bitcoin remains secure under existing computational paradigms. Only once fault-tolerant quantum machines with millions of qubits exist could a real cryptanalytic threat emerge, the report and supporting industry voices said.
The firm also cautioned against premature protocol changes aimed at quantum resistance, warning that rushed upgrades or sweeping interventions — such as callback soft forks or forcibly burning vulnerable coins — could pose their own risks to decentralization and network stability. Gradual, voluntary transitions to quantum-secure address types remain a preferred path for many developers and analysts.
Industry Takeaways
CoinShares’ assessment may reassure investors and developers who have been unsettled by dire quantum threat narratives, but the broader crypto ecosystem continues to watch advancements in quantum hardware with interest. While practical threats remain distant, discussions around post-quantum cryptography and Bitcoin’s adaptability reflect growing attention to future-proofing major blockchain systems.
