Blockstream CEO Adam Back Blasts Nic Carter Over Bitcoin Quantum Threat Debate

Bitcoin's security bedrock just got a public stress test—and the sparks are flying.

Blockstream founder Adam Back just cut through the quantum computing hype with a sharp rebuttal to Castle Island Ventures' Nic Carter. The dispute centers on whether future quantum machines could crack Bitcoin's cryptographic shields.

The Core of the Clash

Back argues the threat is wildly overblown and technically misunderstood. He points to existing research on quantum-resistant algorithms and Bitcoin's inherent upgrade path. For him, it's a theoretical storm in a cryptographic teacup—one that distracts from real-world adoption.

Carter's warnings, meanwhile, frame it as a long-term existential risk that the community can't afford to ignore. It's a classic battle between pragmatic engineering and risk-averse foresight.

The market, of course, barely blinked—too busy chasing the next memecoin pump to worry about decryption threats decades out. A perfect reminder that in crypto, short-term speculation always trumps long-term survival.

So, while the experts duel over future physics, the network keeps humming. Bitcoin's real quantum leap? Surviving another cycle of human drama.

Adam Back Says Bitcoin Developers Are Quietly Preparing for Quantum Risks

Back argued that the Bitcoin ecosystem is not ignoring the long-term risks posed by quantum computing.

Instead, he said developers and researchers are already working on potential protections, but prefer to do so without turning the issue into a public spectacle.

In his view, the discussion has become distorted by exaggeration rather than grounded technical assessment.

Carter rejected that characterization, saying a significant portion of the Bitcoin community remains unwilling to seriously confront the issue.

He claimed many developers are still in “total denial” about the possibility that sufficiently powerful quantum machines could, one day, undermine Bitcoin’s cryptographic foundations.

While the investment itself only recently resurfaced in online debates, Carter noted that he disclosed Castle Island’s backing of Project Eleven weeks earlier.

Others are working on it, and not everyone can work on it as it's cryptography and newer algorithms. As you may know @Blockstream research has been driving and collaborating on Bitcoin related crypto like Schnorr, MuSig, Taproot etc for years. And so it is now with PQ and others

In an Oct. 20 Substack post, he said the disclosure was made upfront. “I disclosed this in the first sentence of my main article on quantum. Can’t get more transparent than that,” Carter said.

Carter described himself as having been “quantum pilled” by Project Eleven CEO Alex Pruden, saying the conversations convinced him that quantum computing poses a serious, if not immediate, risk to blockchain systems.

“I became extremely concerned about quantum threats to blockchains. I put capital behind my convictions, always have,” he said, adding that he expected criticism and made his financial exposure clear in advance.

In laying out his case, Carter pointed to governments preparing for a post-quantum world, rising investment in quantum firms, and the idea that Bitcoin itself could act as a powerful incentive for breakthroughs in quantum technology.

Bitcoin Quantum Debate Deepens as Timelines and Risks Divide Investors

The debate extends beyond Back and Carter.

Capriole Investments founder Charles Edwards recently warned that quantum computing could become a real threat to Bitcoin within two to nine years unless the network upgrades to quantum-resistant cryptography.

Others remain skeptical. Multimillionaire investor Kevin O’Leary has argued that using quantum machines to attack Bitcoin WOULD be a poor use of the technology, suggesting far greater value lies in fields like medical research and artificial intelligence.

Back has acknowledged the importance of preparing Bitcoin to be “quantum ready,” but maintains that practical threats remain decades away, describing the technology as still “ridiculously early” and constrained by major research hurdles.