Quantum computing has long been viewed as a threat to cryptocurrencies, a technology that could one day crack the cryptography securing Bitcoin and other blockchains. In 2026, that fear is resurfacing as major tech firms accelerate quantum research and investment.
While the technology is not yet ready for widespread use, the pace of investment and experimentation has gained traction. In February, Microsoft its Majorana 1 chip, which the company dubbed “the world’s first quantum chip powered by a new Topological Core architecture,” rekindling debate about how quickly quantum hardware might move from research into real-world systems.
However, despite growing attention, most experts say the risk to crypto remains theoretical, not imminent. The real concern, they argue, is not a sudden cryptographic collapse next year, but what attackers are already doing today to prepare for a post-quantum future.
Clark Alexander, co-founder and head of AI at Argentum AI, told Cointelegraph that he expects quantum computing to find “extremely limited commercial use” in 2026.
Nic Puckrin, crypto analyst and co-founder of Coin Bureau, was more blunt. “The whole ‘quantum threat to Bitcoin’ narrative is 90% marketing and 10% imminent threat… we’re almost certainly at least a decade away from computers that can actually break existing cryptography,” he said.
Why cryptocurrencies are at risk
Bitcoin () and most major blockchain networks rely on public-key cryptography to secure wallets and authorize transactions. Private keys sign transactions, public keys verify them, and hash functions secure the ledger. If a future quantum machine can derive private keys from public keys, funds could theoretically be stolen at scale.
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The issue has even reached US regulators. In September, the US Securities and Exchange Commission (SEC)’s crypto task force that quantum computing could eventually break the encryption protecting Bitcoin and other digital assets.
At the technical level, consensus among cryptographers is that signatures are the weakest link. “Any cryptographic system whose security relies on a mathematical problem that Shor’s algorithm can efficiently solve (difficulty of factoring large semiprimes),” said Sofiia Kireieva, blockchain R&D and subject-matter expert at Boosty Labs.
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She added that if a quantum-capable adversary targeted Bitcoin or a similar blockchain, the elliptic curve digital signature algorithm (ECDSA) used for private-public keys would be the “weakest link.” In contrast, the SHA-256 hash functions are much less vulnerable. Grover’s algorithm could at best give a quadratic speed-up, which is mitigated by using larger hashes, according to Kireieva.
Ahmad Shadid, founder of the Switzerland-based O Foundation, also said that signatures are the core vulnerability. “The cryptographic component that would be most vulnerable is the ECDSA digital signature algorithm, specifically, the security of public/private key pairs used to sign transactions, and especially with address reuse (this significantly increases vulnerability),” he said.
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What experts expect in 2026
Despite rising concern, major technical barriers make a cryptographic collapse by 2026 highly unlikely.
Kireieva noted the physics barrier facing quantum hardware. “Current quantum devices have only hundreds or thousands of noisy qubits, it’s far below what’s needed to run deep algorithms like Shor’s… This means a realistic cryptanalytic attack would demand millions of physical qubits, ultra-low gate error rates, and the ability to perform millions of sequential operations without losing coherence,” she said.
Kireieva added that this would also require breakthroughs in materials science, quantum control, fabrication and signal isolation. “The bottleneck is not just engineering — it is the fundamental physics of the universe,” she said.
Alexander took this even further. He said that quantum computers are not only unlikely to break Bitcoin’s encryption by 2026, but may never do so under current approaches. He said that the real danger lies elsewhere, arguing that advances in classical computing pose a greater risk to encryption than quantum systems, and that both quantum and conventional machines would require fundamentally new algorithms before public-key cryptography could be realistically compromised.
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The “harvest now, decrypt later” problem
Meanwhile, the real threat in 2026 is not that Bitcoin breaks; it is that attackers are already collecting data.
“The quantum threat coming to life in 2026 is highly unlikely,” said Sean Ren, co-founder of Sahara AI, “but bad actors are already collecting as much encrypted data as possible… so that, when the tech is ready, all that archived data becomes readable.”
Leo Fan, co-founder of Cysic, echoed that view, saying that one typical attack scenario is “harvest now, decrypt later,” where adversaries are already collecting sensitive encrypted data to unlock once quantum breakthroughs arrive.
Shadid explained that this means that someone could be downloading terabytes of this publicly accessible onchain data simply to collect public keys, which can then be used with a quantum computer to decode private keys.
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Millions of Bitcoin remain exposed: How is crypto preparing?
Kireieva estimated that 25%–30% of all BTC (around 4 million coins) are in vulnerable addresses, addresses whose public keys have already been exposed onchain, making them more susceptible to private-key recovery by a sufficiently powerful quantum computer.
She advised users to minimize exposure by avoiding address reuse, ensuring public keys remain hidden until funds are spent, and staying prepared to migrate to quantum-resistant wallets and address formats as soon as they become available.
The crypto community has also taken practical steps. In July, cryptography to replace Bitcoin’s current signature systems with quantum-resistant alternatives, noting that about a quarter of Bitcoin’s funds are already exposed due to public keys being revealed onchain.
In November, Qastle plans to bring quantum-grade security to hot wallets by upgrading the cryptography behind the scenes. Instead of relying on predictable software-based randomness, it uses quantum-generated randomness and post-quantum encryption to protect keys, transactions and communications, all without extra hardware or complicated setup.
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The crypto industry faces no quantum doomsday in 2026. However, the conversation about the threat of shifts from “if” to “when.”
“The likelihood that a major quantum attack… occurs by 2026 is low-to-moderate,” Fan said. “However, the likelihood that quantum becomes a top-tier risk factor for crypto security awareness in 2026… is high,” he added.
