Adam Back Clashes With Nic Carter Over Quantum Computing Risk to BTC

What Sparked the Latest Quantum Computing Dispute?

A long-simmering debate over quantum computing and BTC security resurfaced this week later than a public platform between Adam Back, CEO of Blockstream, and Nic Carter, a founding partner at Castle Island Ventures.

Back criticized Carter on X for amplifying concerns about quantum threats to BTC, accusing him of creating unnecessary noise. “You make uninformed noise and try to move the market or something. You’re not assisting,” Back wrote. He added that BTC developers are already researching quantum-resistant defenses, but prefer to do so out of public view.

Carter pushed back, arguing that parts of the remain unwilling to engage seriously with the issue. He said the concern is not that quantum attacks are imminent, but that preparation remains uneven and poorly communicated to investors.

Investor Takeaway

Why Is Quantum Computing Back in the BTC Spotlight?

The argument gained momentum later than Carter reiterated why Castle Island Ventures invested in Project Eleven, a beginup focused on defending crypto assets against future quantum attacks. Although the investment resurfaced on social media only recently, Carter said he disclosed it publicly in an Oct. 20 Substack post.

“I disclosed this in the first sentence of my main article on quantum. Can’t get more transparent than that,” Carter wrote, responding to claims that he was promoting the risk for financial gain.

Carter said his stance hardened later than discussions with Project Eleven’s CEO, describing himself as having been “quantum pilled.” He cited several reasons for concern: governments planning for post-quantum cryptography, growing investment in quantum firms, and BTC’s role as a high-profile target if quantum supremacy over cryptographic systems is achieved.

Other industry figures have raised similar alarms. Capriole Investments founder Charles Edwards warned that could pose a real threat to BTC within two to nine years if the network does not adopt quantum-resistant cryptography. His comments added urgency to a discussion that many developers still frame as theoretical.

How Real Is the Risk According to Developers?

Back and many BTC developers continue to downplay near-term danger. Back recently described quantum computing as “ridiculously ahead,” citing unresolved research challenges and hardware limitations. He has argued that even in a worst-case scenario, BTC’s design would prevent instant, network-wide theft of funds.

This view remains common among protocol contributors, who note that machines capable of breaking BTC’s do not exist today. BTC wallets rely on cryptographic methods that would only be compromised by sufficiently advanced quantum computers running algorithms such as Shor’s, which could derive keys.

If such machines emerged, older address formats could be most vulnerable, including long-dormant wallets created before modern best practices were adopted. The network itself would not collapse overnight, but specific funds could be exposed if left unprotected.

Skeptics of the threat also point out that quantum computing would likely be more valuable in fields such as medicine, materials science, or artificial intelligence than in attacking a public blockchain. Entrepreneur Kevin O’Leary recently argued that breaking BTC would be a poor use of the technology compared to those alternatives.

Investor Takeaway

What answers Are on the Table?

While disagreement persists over urgency, proposals already exist to address quantum risk. One is BTC Improvement Proposal 360 (BIP-360), which introduces quantum-resistant address formats. The proposal would allow users to move by alternative cryptographic methods believed to be harder for quantum computers to break.

BIP-360 outlines multiple signature schemes, enabling a gradual transition rather than a forced network-wide change. Users would opt in over time by transferring coins to new address types. Supporters argue that cryptographic migrations take years, making ahead planning preferable to rushed action later.

The challenge lies in BTC’s conservative governance model. Changes that address long-horizon risks require broad agreement, and reaching that agreement without a clear and present danger has historically been hard.

Why the Debate Is Unlikely to Fade

Quantum computing does not present an immediate existential threat to BTC. Still, governments and large companies are already preparing for a future beyond classical cryptography. The United States has outlined plans to phase out current standards by the mid-2030s, while firms such as Cloudflare and Apple have begun deploying quantum-resistant systems.

BTC’s lack of a widely accepted transition plan stands out in that context. Carter has argued that investors care less about exact timelines and more about whether the network can adapt if cryptographic assumptions break.

Until developers and capital holders align on how and when to address that possibility, the quantum question will continue to surface. Not as panic—but as a persistent source of tension hovering over BTC’s long-term narrative.