Samson Mow warned that hurried attempts to make Bitcoin quantum-resistant could create fresh risks, responding to calls from Coinbase executives for faster action. Mow, a Bitcoin advocate and founder of Jan3, posted on X after Coinbase CEO Brian Armstrong and CSO Philip Martin urged the industry to begin preparing sooner for quantum-computing threats.
Mow acknowledged that post-quantum (PQ) cryptography can protect Bitcoin against future quantum attacks, but said an expedited implementation risks introducing incompatibilities, larger signatures and degraded network performance. “Simply put: make Bitcoin safe against quantum computers just to get pwned by normal computers,” he wrote, arguing that a poorly timed transition could weaken security against today’s threats while aiming to guard against a distant one.
His warning revived broader debate about how to future-proof Bitcoin, after recent research from Google and theory from Caltech researchers renewed concerns about quantum progress. One practical worry is signature size: former Bitcoin developer Jonas Schnelli estimated PQ signatures could be 10–125x larger than current ones, which would substantially reduce throughput and could pressure increases to block size—a scenario Mow called a potential “Blocksize Wars 2.0.”
The original block size disputes, which heightened between 2015 and 2017, centered on scaling, decentralization and control of Bitcoin’s roadmap; that episode ultimately led the community to pursue alternative scaling approaches rather than a simple block-size increase. Mow said that while he opposes rushing a network-wide PQ rollout, research and preparation should continue. He noted quantum computers likely won’t be operational for another 10–20 years, so the “worst possible course of action is to rush a fix,” even as ongoing work to assess and design solutions remains important.