A new brief from the Bitcoin Policy Institute argues that recent breakthroughs in quantum computing are accelerating the timeline for when Bitcoin’s cryptography could face credible threats, while stressing that developers are already preparing solutions.
In its report, State of Play: Quantum Computing and Bitcoin’s Path Forward, the Bitcoin Policy Institute points to two research papers released on March 31 by Google and California Institute of Technology that reshape long-standing assumptions about the computing power required to break Bitcoin’s encryption.
For years, estimates suggested that an attacker would need around 10 million qubits to exploit Shor’s algorithm and compromise Bitcoin’s security model. According to the Bitcoin Policy Institute’s analysis of Google’s findings, that threshold could be reduced to fewer than 500,000 qubits. A separate paper involving Caltech and University of California, Berkeley indicates that specialized quantum systems could lower that requirement further, to a range between 10,000 and 26,000 qubits.
The Bitcoin Policy Institute notes that the two papers take different approaches—one emphasizing software efficiency and the other hardware design—but arrive at the same conclusion: the resource requirements for a quantum attack are declining.
Despite that shift, the organization emphasizes that Bitcoin is not under immediate threat. Current quantum machines remain far below the levels outlined in the research. Google’s most advanced processor, Willow, operates with just over 100 qubits, leaving a wide gap between theory and practical capability.
Still, the Bitcoin Policy Institute frames the findings as a signal that preparation must continue at pace. The report highlights ongoing efforts within the Bitcoin developer community to address long-term risks tied to quantum computing.
Central to that work is BIP-360, a proposal that the Bitcoin Policy Institute describes as one of the most active areas of development in the protocol’s history. The proposal introduces a new address format that prevents public keys from being exposed during transactions, removing a key vulnerability that quantum attackers could exploit.
The Bitcoin Policy Institute points to a testnet launched in March that has already attracted more than 50 miners and over 100 cryptographers. The level of participation, the group argues, reflects strong alignment across technical contributors.
The report also underscores that Bitcoin’s existing architecture provides flexibility. The Taproot upgrade, activated in 2021, includes features that can support quantum-resistant verification methods through alternative spending conditions.
Beyond the Bitcoin ecosystem, the Bitcoin Policy Institute situates the issue within a broader policy context. The National Institute of Standards and Technology finalized post-quantum cryptographic standards in 2024, offering tools that can be adapted for Bitcoin. Federal agencies have been given a 2035 deadline to transition to quantum-resistant systems, while Google has set an internal target of 2029.
Bitcoin’s decentralized structure is a challenge
The Bitcoin Policy Institute stresses that Bitcoin’s decentralized structure introduces a distinct challenge. Unlike governments or corporations, the network cannot mandate upgrades. Any change must emerge through consensus among participants.
Even so, the report points to past upgrades as evidence that coordination is possible. With quantum security, the Bitcoin Policy Institute argues, incentives are aligned across the network, as all stakeholders depend on maintaining system integrity.
The report concludes that the quantum threat is not imminent, but the timeline is tightening. In the Bitcoin Policy Institute’s view, the technical solutions are already taking shape, and the focus now shifts to how the network reaches agreement on deployment.
Yesterday, a new research proposal from StarkWare’s Avihu Levy introduced “Quantum Safe Bitcoin” (QSB), a scheme designed to protect Bitcoin transactions from future quantum attacks without requiring changes to the network’s core protocol.
The approach shifts security away from vulnerable ECDSA signatures toward hash-based assumptions, aiming to guard against threats like Shor’s algorithm while remaining compatible with Bitcoin’s existing system.
