Fidelity Digital Assets has published new research analyzing potential risks future quantum computers may pose to Bitcoin’s core cryptographic security. The report, released on September 1, examines whether quantum breakthroughs could undermine the way Bitcoin private keys protect funds.
Quantum Threats to Bitcoin Security
Current quantum computers remain uncapable of breaking modern cryptography. However, ongoing advancements have encouraged Bitcoin developers and researchers to assess how well the network’s cryptography will stand up if quantum computing makes a major leap.
The main concern centers on the mathematical problems behind Bitcoin’s private and public key pairs. Today, private keys allow users to sign and approve transactions independently, without the need for intermediaries.
While signatures generated by private keys do not expose the underlying key, the foundation of their security relies on the difficulty for traditional computers to reverse-engineer a private key from a public key.
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AAPLFidelity’s team pointed to the growing awareness that, if quantum computers evolve to run Shor’s algorithm at sufficient scale, they could theoretically reconstruct a private key from its linked public key. This risk prompted further exploration of long-term cryptographic improvements for Bitcoin.
Transitioning to Quantum-Resistant Signatures
Most transactions on the Bitcoin network use either the Elliptic Curve Digital Signature Algorithm (ECDSA) or Schnorr signatures, with the latter enabled after the Taproot upgrade in 2021. Both rely on computational problems that are currently unsolvable for classical computers, but potentially vulnerable to advanced quantum machines.
Researchers are now investigating cryptographic alternatives designed to withstand quantum computing. One proposal, known as SHRINCS, would use signatures based on hash functions rather than elliptic curves, introducing both a compact, stateful signature and a larger, stateless backup signature system.
The proposed SHRINCS setup features a 48-byte public key, with stateful signatures ranging from 548 to 4,619 bytes, while stateless signature backups use 5,777 bytes. The stateful approach would require devices to monitor which single-use keys have already been used, creating new wallet management challenges.
Researchers explained that a stateless backup, based on the new NIST SLH-DSA standard published in August 2024, could allow continued access to funds but at the cost of larger blockchain footprints and increased transaction fees.
Adopting quantum-resistant signature schemes like SHRINCS would also require a change in Bitcoin’s consensus rules, typically through a backward-compatible soft fork. The upgrade would require broad collaboration among wallet providers, miners, exchanges, and node operators—a process that historically unfolds slowly across the industry.
Industry Initiatives and Future Outlook
In July, Fidelity partnered with eight other financial and crypto firms to collectively fund a $15 million Bitcoin security initiative. This program focuses on researching practical quantum-resistant safeguards and adapting them to Bitcoin’s technical limitations.
Fidelity’s review highlighted that even small increases in transaction data size for quantum-resistant signatures could substantially affect network throughput and user costs. For now, the impact remains limited while Bitcoin’s mempool experiences low activity, but future network congestion could amplify fee and speed issues.
Experts noted that while quantum computers capable of attacking Bitcoin’s cryptography are not yet available, the risk horizon means preemptive planning for quantum resistance is increasingly vital.
As the market rapidly evolves, even a single regulatory decision or an unexpected coin listing can transform conditions in seconds. To keep up, sophisticated traders are relying on integrated, privacy-first platforms such as CryptoAppsy, which offers real-time charts, smart alerts, coin-specific updates, and essential macro data on one unified screen—streamlining decision-making without requiring user accounts.
While quantum computing threats remain a longer-term consideration, Bitcoin stakeholders are accelerating research and collaboration to defend the network’s core security into the future.
