Bitcoin and Quantum Computing: Why the Threat Is Still Decades Away

Blockstream CEO Adam Back has pushed back against growing public warnings about quantum computing risks to Bitcoin, criticizing a prominent venture capitalist for fueling what he called “uninformed noise” within the Bitcoin community.

Adam Back rejects public quantum fear narrative

Blockstream CEO Adam Back has criticized Castle Island Ventures founding partner Nic Carter for amplifying concerns about quantum computing threats to Bitcoin.

In a post on X on Friday, Back accused Carter of spreading “uninformed noise” and suggested such comments were unhelpful for Bitcoiners. His remarks followed Carter’s explanation of why Castle Island Ventures invested in Project Eleven, a startup focused on protecting Bitcoin and other crypto assets from potential quantum threats.

Back argued that the Bitcoin community is not ignoring the issue. Instead, he said developers are already researching quantum-resistant solutions, but prefer to do so quietly rather than fueling public fear.

Carter disputes claims of denial

Nic Carter strongly disagreed with Back’s assessment. He said many Bitcoin developers remain in “total denial” about the risks posed by quantum computing.

While the investment in Project Eleven recently resurfaced on social media, Carter noted that he had already disclosed it publicly. He pointed to an Oct. 20 Substack post where he revealed the investment in the opening sentence, emphasizing transparency around his financial exposure. “I knew the bad faith criticisms would come,” Carter said, adding that he made sure to clearly disclose his involvement.

Why Carter sees quantum computing as a risk

Carter said his concerns grew after discussions with Project Eleven CEO Alex Pruden, who he said “quantum pilled” him. According to Carter, the investment reflects a genuine belief that quantum computing could pose future risks to Bitcoin.

He outlined several reasons for concern. These include governments preparing for a post-quantum world, Bitcoin acting as a potential incentive for quantum breakthroughs, and rising investment into quantum technology firms. Carter is not alone in raising public warnings. Several prominent figures have recently echoed similar concerns.

How soon could quantum threats emerge?

Capriole Investments founder Charles Edwards warned that quantum computing could become a real threat to Bitcoin within two to nine years if the network does not upgrade to quantum-resistant cryptography.

Others take a more cautious view. Entrepreneur Kevin O’Leary recently said breaking Bitcoin’s security would not be the most efficient use of quantum computing. He argued the technology would likely deliver greater value in fields such as AI-driven medical research.

Back himself has acknowledged the importance of long-term preparation. He said it is good for Bitcoin to be “quantum ready,” but added that quantum computing remains in a very early stage and is unlikely to pose a serious threat for decades.

Debate highlights split within Bitcoin community

The disagreement underscores a broader divide within the Bitcoin community. Some argue that public discussion is necessary to accelerate preparedness. Others believe overstating near-term risks creates unnecessary fear. For now, the debate reflects a tension between proactive caution and confidence in Bitcoin’s long-term security model as quantum computing continues to evolve.