CoinShares published a report arguing that quantum computers do not pose a real risk to Bitcoin in the immediate future. One of the key points the company makes is that there is still a huge gap between the capabilities of current computers and the ability to break Bitcoin’s signatures.
The discussion surrounding quantum computing and Bitcoin often focuses on the potential vulnerability of ECDSA signatures to Shor’s algorithm. However, CoinShares put this risk into perspective by pointing out that running Shor at an operational scale would require approximately 13 million physical qubits to invert a public key in just one day, and even more to enable realistic attack windows. Given that current quantum machines only reach a few hundred unstable qubits, the threat clearly shifts to the medium and long term.
Along the same lines, the report emphasized the significant technological gap. CoinShares estimated a development horizon of between 10 and 30 years before quantum capabilities exist that pose a practical risk to Bitcoin. This implies that, far from being an immediate danger, the challenge should be viewed as a matter of planning and technological evolution, rather than an operational urgency for the current market.
On the other hand, the SHA-256 hash function does not appear to be a critical weakness. Although Grover’s algorithm would reduce its effective security from 256 to approximately 128 bits, that level remains impractical to attack by brute force, even with advanced quantum computers.
Furthermore, CoinShares noted that quantum miners would face economic and engineering barriers compared to specialized ASICs, while automatic difficulty adjustment acts as an additional buffer against any sudden disruption.
Limited Exposure and Adaptability of the Protocol
A key aspect of the analysis is that not all bitcoins are equally exposed. Most modern address formats hide the public key until the funds are spent, drastically reducing the attack window. According to CoinShares, the directly vulnerable amount is limited to approximately 10,200–10,230 BTC, concentrated in older Pay-to-Public-Key (P2PK) outputs—a very small fraction of the total supply and generally locked in inactive UTXOs that have been dormant for years.
Even in the hypothetical scenario of these coins being compromised, the market impact wouldn’t necessarily be systemic. CoinShares argued that the effect would resemble large, gradual sell-offs more than an abrupt collapse, as attackers would face the same liquidity and execution frictions as any large holder attempting to monetize their assets.
At the same time, Bitcoin’s design offers a clear path for evolution. The ecosystem already has technical precedents, such as the introduction of Schnorr signatures, and there is active work on post-quantum cryptography, supported by standards bodies like NIST.
Overall, CoinShares frames the quantum challenge as an engineering problem with observable indicators and sufficient time to react. For custodians and market participants, practical steps involve monitoring the evolution of cryptographically relevant qubits, closely following emerging standards, and prioritizing the migration of legacy holdings.
