Alex Thorn, Head of Research at Galaxy Digital, has warned that the potential threat of quantum computers to the long-term cryptographic security of Bitcoin is real, even if such a risk remains distant for now. While quantum hardware is not yet capable of breaking Bitcoin’s defenses, Thorn emphasized that preparations should begin before such capabilities materialize. Galaxy Digital is a prominent player in the cryptocurrency, financial services, and blockchain sectors, while Bitcoin itself stands out as the first decentralized and blockchain-based digital currency.
Main Takeaways from the Report
In his recent report, Thorn noted that quantum computers are still years—if not decades—away from reaching the power needed to threaten Bitcoin’s core cryptographic algorithm, the Elliptic Curve Digital Signature Algorithm (ECDSA). Current quantum machines lack the logical qubit capacity to perform this type of computation. This gap means that, although the risk is genuine, it remains largely theoretical at present and does not pose an immediate concern.
At-Risk Bitcoin Addresses
The report highlights that the threat posed by quantum computing is not uniform across all Bitcoin addresses. Wallets remaining from Bitcoin’s early days—especially those from the Satoshi Nakamoto era equipped with repeated addresses or unspent transaction outputs (UTXOs)—are far more vulnerable because their public keys are openly visible on the blockchain. In contrast, modern Pay-to-Public-Key-Hash (P2PKH) addresses only reveal their public keys once a transaction is broadcast, making it harder for attackers. In these cases, an adversary would need to intercept and use the public key before the transaction is completed, offering greater security overall.
This means that legacy addresses dating back to the Satoshi era are particularly sensitive. The fate of assets tied to these older addresses—whether they will be moved to quantum-resistant formats—remains uncertain.
Developers Take Precautionary Steps
According to Galaxy’s report, the Bitcoin developer community is not ignoring the quantum risk; on the contrary, research into Post-Quantum Cryptography is ongoing. The Taproot upgrade implemented in 2021 laid the technical groundwork for more complex scripting types, potentially paving the way for advanced signature systems like Lamport or Winternitz that are believed to be quantum-resistant in the future.
The report suggests that a potential ‘soft fork’ could facilitate user migration to new quantum-secure addresses. Thorn draws a parallel to the lengthy transition from legacy addresses to SegWit addresses—a process that took years—while warning that the stakes are significantly higher with a quantum migration due to the elevated risk involved.
Bitcoin’s intentionally slow and cautious approach to upgrades is both a security policy and a practical constraint, according to the report. In comparison, Ethereum’s roadmap for quantum security is moving more quickly. Experiences from Ethereum’s progress could serve as a model for other blockchain projects facing similar threats.
Alternate Quantum Threat: “Harvest Now, Decrypt Later”
Thorn called attention to one of the lesser-discussed quantum risks: State-level actors might be archiving today’s encrypted digital communications with the intention of decrypting them in the future, once quantum computing prowess advances. While this scenario poses a grave danger for private communications and particularly sensitive information, it is less applicable to Bitcoin’s openly visible balances, where the immediate impact would be limited.
The report also notes that by the time quantum computers are publicly known to be powerful enough, the window to secure the most vulnerable Bitcoin addresses may have already closed completely.
Market Ignores Quantum Computing Risks
Bitcoin’s price continues to trade around $70,000, with institutional players showing little sign of anxiety over quantum-related threats. Despite notable advances in quantum error correction by major firms like IBM and Google, Thorn notes that the absence of widespread concern mirrors the industry’s consensus that there is no looming crisis. Markets tend to focus more on short-term developments, and as such, long-term technical risks like quantum computing have yet to be factored into current valuations.
