Phase A begins three years after P2QRH goes live and “disallows sending of any funds to quantum-vulnerable addresses,” forcing new coins toward quantum-safe scripts.
Phase B follows two years later, on a pre-announced flag day, when “nodes reject transactions that rely on ECDSA/Schnorr keys,” rendering legacy outputs unspendable.
Phase C is optional and, pending further research, could enable owners who missed the deadline to recover funds with a zero-knowledge proof of possession of their BIP-39 seed.
The document’s rationale is explicit: “A successful quantum attack on Bitcoin would result in significant economic disruption and damage across the entire ecosystem.” By imposing a known deadline, the authors hope to overcome what they describe as “upgrade inertia” among wallets, exchanges and custodians that historically stretches protocol roll-outs over many years.
Each stakeholder cohort is offered a blunt calculus. Miners risk producing “invalid blocks” after Phase B if they do not upgrade, but in the interim can expect heavier blocks and higher fees from the larger post-quantum signatures. Institutional holders face potential fiduciary liability should they ignore the migration timetable, while exchanges confront the prospect of overnight insolvency if quantum attackers drain custodial hot wallets. For individual users, the sunset date converts an abstract, far-off threat into a hard deadline.
A notable corollary is that coins abandoned in quantum-vulnerable scripts would become permanently frozen, echoing Satoshi’s early observation that “lost coins only make everyone else’s coins worth slightly more.” The proposal inverts that logic for quantum-recovered coins, calling them “a theft from everyone.”
For now, the authors have thrown down a clear gauntlet: either the ecosystem coordinates on a proactive timeline, or it faces the prospect of responding to an emergency only after the first quantum theft has occurred.
At press time, BTC traded at $118,623.
