More than one-third of Bitcoin’s circulating supply may be exposed to quantum-era vulnerabilities, according to a new draft proposal from core researchers. The finding reframes long-term network security as a timing problem, not a theoretical one.
The proposal, outlined in BIP-361, introduces a phased plan to restrict transactions tied to legacy signature schemes. It targets outputs with exposed public keys, including early pay-to-public-key formats, and sets a multi-year deadline for migration to quantum-resistant alternatives.
Can Bitcoin Enforce A Mandatory Shift To Quantum Safety?
The approach reflects a shift toward proactive defense as quantum timelines compress. Google recently suggested practical attacks could emerge by 2029, tightening earlier assumptions about distant risk. By contrast, Benchmark analysts have argued the threat remains manageable, highlighting a growing divergence in industry expectations.
Under the plan, the first phase would block new transactions sent to vulnerable address types, while later stages would invalidate signatures based on Elliptic Curve Digital Signature Algorithm (ECDSA) and Schnorr entirely. That would effectively freeze unmigrated funds, forcing upgrades across wallets, exchanges, and custodians within a defined window.
The rigidity has drawn mixed reactions. Some researchers view the proposal as a necessary constraint to reduce systemic risk, while others frame it as premature. Bernstein analysts have described the shift as a routine upgrade cycle, while Michael Saylor has dismissed quantum concerns as overstated, arguing the network retains sufficient time to adapt.
Still, the absence of consensus is evident. Alternative designs, including a proposal from a StarkWare researcher to enable quantum-safe transactions without a soft fork, point to competing technical paths. With Bitcoin historically slow to coordinate protocol changes, the next catalyst will likely hinge on whether developers converge around a single upgrade framework before quantum timelines tighten further.
