Rushed quantum fix may backfire for Bitcoin, Samson Mow warns

Rushed quantum fixes for Bitcoin could introduce new risks, Samson Mow warned in response to calls from Coinbase executives for faster action.

Mow, a Bitcoin advocate and Jan3 founder, took to X on Saturday to address comments from Coinbase CEO Brian Armstrong and chief security officer Philip Martin, who urged the industry to begin preparing for quantum computing threats sooner rather than later.

He said that while post-quantum (PQ) cryptography could secure Bitcoin (BTC) against future quantum computers, rushing implementation may create new vulnerabilities such as compatibility issues and reduced network efficiency due to larger signature sizes.

“Simply put: make Bitcoin safe against quantum computers just to get pwned by normal computers,” Mow said, adding that a poorly timed transition could weaken Bitcoin against today’s threats before addressing future ones.

The exchange reflects a growing debate over how to future-proof Bitcoin, as new research from Google and Caltech reignited concerns about progress in quantum computing.

Why Mow is pushing back and how it ties to the block size wars

One of Mow’s biggest concerns about rushing a quantum fix for Bitcoin is the potential impact on performance, particularly block size, or the amount of transaction data that can fit into a single block.

“PQ signatures will likely be 10-125x larger than current ones, and massively reduce throughput,” Mow said, citing former Bitcoin developer Jonas Schnelli.

The signature issue could potentially pave the way for “Blocksize Wars 2.0,” Mow continued.

Bitcoin’s block size wars began around 2015 and peaked in 2017, when the community split over whether to increase the block size to handle more transactions.

Related: Circle unveils quantum-resistant roadmap for its layer-1 blockchain Arc

That dispute raised concerns about decentralization, network security and who controls Bitcoin’s future, ultimately leading to alternative scaling solutions rather than a simple increase in block size.

Despite arguing against rushing a transition to post-quantum cryptography for Bitcoin, Mow said work on potential solutions should continue.

“Given that quantum computers don’t actually exist and likely won’t exist for another 10-20 years, the worst possible course of action is to rush a fix,” he said. “That’s not to say work shouldn’t be done to prepare, and there is already much work being done.”

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