Bitcoin’s quantum computing debate got messier this week. Three proposals compete for community support, and they agree on nothing.
Adam Back: Build Quantum-Resistant Tools, Trust the Process
Adam Back, CEO of Blockstream, told Paris Blockchain Week attendees on Wednesday that Bitcoin should start building optional quantum-resistant signature schemes now, while the threat remains distant. Let users migrate at their own pace. Trust that developers can move fast enough when it matters.
“Bugs have been identified and fixed within hours,” he said. “When something becomes urgent, it focuses attention and drives consensus.”
Blockstream has been testing quantum-resistant signatures on Liquid, Bitcoin’s sidechain. Back’s argument is that the groundwork can be laid without touching anything the current network depends on.
Lopp’s BIP-361: Freeze the Coins or Lose Them
Jameson Lopp published BIP-361 this week alongside five co-authors. Phase out quantum-vulnerable addresses over five years, and freeze any coins that fail to migrate. That includes the roughly one million bitcoin attributed to Satoshi Nakamoto and an estimated 5.6 million coins that have not moved in over a decade.
Lopp’s position is that Bitcoin’s consensus process will not hold together under real crisis conditions, and a fixed deadline is the only way to avoid panic. Back did not mention BIP-361 by name, but his framing rejected everything it stands for.
BitMEX Proposes a Quantum Tripwire Instead
BitMEX Research took a different angle: don’t freeze anything yet, but set a trap. The idea is a “canary fund,” a Bitcoin address built so that nobody knows the private key. Under current technology it is unspendable. If it is ever drained, something with real quantum capability just did it, and that triggers the response.
No preemptive freezes. No forced migrations. Just a wire to trip. The weakness is the same as Back’s: it still assumes everyone can coordinate fast enough once the alarm sounds.
Why Bitcoin’s Quantum Security Debate Is Happening Now
For years, quantum computing was something Bitcoin developers filed under “eventually.” Two recent papers moved it closer. Google Quantum AI published research in March suggesting functional quantum computers capable of breaking Bitcoin’s cryptography could arrive around 2032, sooner than most previous estimates. A separate paper argued the resources required may be lower than previously thought.
Back still calls current hardware “essentially lab experiments.” The most advanced machines have managed to factorize 21 into 7 times 3, a calculation any primary school child can do. But the research has shifted enough to force a real question: can Bitcoin’s rough-consensus model handle a threat that arrives slowly, then all at once?
Nobody has a consensus answer yet.
