A new report from Coinbase’s Independent Advisory Board on Quantum Computing and Blockchain has reignited concerns about the long-term security of Bitcoin. According to the study, nearly 7 million bitcoin—roughly one-third of the total supply currently in circulation—could eventually become vulnerable if quantum computing technology advances to the point where it can defeat today’s cryptographic protections.
While no existing quantum computer can break Bitcoin’s security mechanisms, experts argue that preparation must begin years before such capabilities emerge. The issue has evolved beyond a technical challenge and is now becoming a critical governance question for the cryptocurrency industry.
Researchers identified two major categories of potentially exposed bitcoin. The first includes approximately 1.7 million BTC held in older Pay-to-Public-Key (P2PK) addresses. These early Bitcoin addresses reveal public keys directly on the blockchain, making them a potential target in a future quantum-enabled environment.
The second and significantly larger category involves about 5 million BTC linked to address reuse. In these cases, public keys have already been exposed through previous transactions, increasing theoretical vulnerability if quantum computers become powerful enough to derive private keys.
Why Quantum Computing Matters
Bitcoin’s security relies primarily on cryptographic signature systems known as ECDSA and Schnorr signatures. Under current computing standards, cracking these systems would require an impractical amount of time and resources.
Quantum computers, however, operate using entirely different principles that could dramatically reduce the complexity of such calculations.
Major technology companies are investing heavily in quantum research:
- Google is targeting a transition to post-quantum cryptography by 2029.
- IBM continues expanding enterprise quantum computing initiatives.
- Microsoft is developing quantum-safe security solutions.
- Governments worldwide are funding next-generation cryptographic research.
Although experts agree the threat remains years away, advancements in quantum hardware have accelerated significantly over the past decade. As a result, cybersecurity planners increasingly view early preparation as essential rather than optional.
Bitcoin Community Faces Key Decisions
The report highlights a growing divide within the Bitcoin ecosystem over how vulnerable coins should be handled in the future. One group supports requiring users to migrate funds into quantum-resistant wallets before a predetermined deadline.
Any coins left behind would become permanently inaccessible, preventing potential quantum attackers from moving them.
Opponents argue that freezing coins would violate Bitcoin’s foundational principles by interfering with property rights and setting a precedent for network intervention.
Several compromise proposals have emerged, including Hourglass, which would limit the movement of vulnerable coins, and BIP-361, which would gradually replace older signature methods with quantum-resistant alternatives. Another proposal, known as PACTs, would allow users to commit to future quantum-safe transfers without immediately moving assets.
Perhaps the report’s most significant finding is that active holdings, including exchange reserves and institutional wallets, may present a greater risk than dormant early-era bitcoin. This shifts the conversation from a theoretical concern to a practical challenge affecting millions of users worldwide.
For now, Bitcoin remains secure. Yet the warning underscores a growing reality: adapting to the quantum era may become one of the most important challenges in the cryptocurrency’s history.