Blockstream CEO: Quantum Computing Won’t Crack Bitcoin Before 2050—Here’s Why

Quantum computing's existential threat to Bitcoin? Not happening anytime soon.

Adam Back, Blockstream's CEO and cryptography pioneer, just dropped a truth bomb: even with quantum leaps in tech, Bitcoin's armor stays impenetrable for decades.

The countdown to doomsday? Reset.

While Wall Street hedge funds pour billions into quantum startups chasing 'unbreakable' trading algorithms, Bitcoin's SHA-256 encryption laughs in superposition. Back estimates it'd take a 1-million-qubit computer to brute-force a wallet—current lab prototypes barely scratch 1,000.

Meanwhile, traditional finance keeps playing checkers.

Banks spent $42B last year 'future-proofing' systems against hypothetical threats... while still running 1970s-era SWIFT rails. Priorities.

Quantum hype meets cryptographic reality—and for once, the nerds win. Sleep tight, HODLers.

TLDR

• Adam Back, CEO of Blockstream, states that Bitcoin is safe from quantum threats for the next 20 to 40 years.
• The National Institute of Standards and Technology has already approved post-quantum encryption standards for Bitcoin.
• Quantum computers today are too small and noisy to break Bitcoin’s SHA-256 encryption, according to Back.
• Experts, including Back have dismissed concerns about a quantum attack within two to five years.
• Bitcoin’s security may be upgraded with quantum-resistant signatures before quantum computers reach the necessary power.

Bitcoin is not at risk from quantum computing for at least two to four decades, according to Adam Back, CEO of Blockstream. Back, a cryptographer cited in the original Bitcoin white paper, responded to concerns about quantum attacks. He emphasized that the current fears surrounding quantum threats to Bitcoin’s security are overstated.

Back clarified his stance in response to a concerned user’s tweet, explaining that Bitcoin’s current encryption method, SHA-256, remains secure for the foreseeable future. Back stated, “Bitcoin is probably not vulnerable for 20–40 years.”

He referred to the National Institute of Standards and Technology’s post-quantum encryption standards as a safeguard for the cryptocurrency. These standards, he argued, could be adopted before quantum computers are capable of breaking SHA-256 encryption.

Probably not for 20-40 years, if then. And there are quantum secure signatures, NIST standardized SLH-DSA last year. bitcoin can add over time, as the evaluation continues and be quantum ready, long before cryptographically relevant quantum computers arrive.

— Adam Back (@adam3us) November 15, 2025

Concerns Over Quantum Computing’s Impact on Bitcoin Security

The fears around quantum computing’s ability to crack Bitcoin’s encryption became more widespread after venture capitalist Chamath Palihapitiya warned of an imminent threat. Palihapitiya predicted that quantum computing could pose a risk within 2 to 5 years. He cited the need for about 8,000 qubits to break Bitcoin’s encryption.

Back rejected this prediction, explaining that today’s quantum machines are too small and noisy to pose a realistic threat. He pointed out that the most extensive neutral-atom system built at Caltech has only 6,100 physical qubits. However, these qubits are not yet stable or error-corrected enough to break current cryptographic systems. Quantum systems, such as Quantinuum’s Helios, are still far from the required number of stable qubits, with only about 48 logical qubits.

Quantum Risks Prompt Bitcoin Security Upgrades

Although practical quantum attacks on Bitcoin are not possible yet, experts continue to monitor long-term risks. One concern is the “harvest now, decrypt later” approach, in which attackers collect encrypted data now and decrypt it once quantum technology advances. While this strategy doesn’t immediately threaten Bitcoin’s ownership model, it underscores the need for timely cybersecurity upgrades.

Bitcoin’s community is already preparing for the eventual quantum threat. Some Bitcoin experts, like on-chain analyst Willy Woo, have warned users to MOVE coins from older address formats. These formats may be vulnerable to quantum attacks before others. Former Bitcoin Core developer Jonas Schnelli stressed that no migration plan will be completely safe once quantum machines can access the mempool.

Bitcoin developers are already discussing potential solutions to prepare for quantum threats. One such solution is Bitcoin Improvement Proposal (BIP) 360, which suggests implementing quantum-resistant ML-DSA signatures. The proposal, drafted by Jameson Lopp, aims for a gradual transition to quantum-resistant signatures before quantum machines pose a threat.

Some developers believe that a protocol-level overhaul will be necessary for reliable protection against quantum threats. Meanwhile, specific companies, such as Rootstock and Naoris Protocol, are exploring post-quantum infrastructure. Even hardware wallets like Trezor’s SAFE 7 are incorporating quantum-secure update paths to future-proof against potential quantum risks.