Quantum computing has been perceived as a potential threat to cryptocurrencies, capable of breaking the cryptography that protects Bitcoin and other blockchains. As we move through 2026, this concern is becoming more pronounced with significant investments and research from major tech companies.
Although the technology is not yet widely applicable, the momentum behind investment and experimentation is increasing. In February, Microsoft revealed its Majorana 1 chip, branded as “the world’s first quantum chip powered by a new Topological Core architecture,” sparking renewed discussions about the pace at which quantum hardware may transition from theoretical research to practical applications.
Nonetheless, despite heightened awareness, most professionals believe the threat to cryptocurrency is still theoretical and not immediate. They assert that the concern lies not in an abrupt failure of cryptography next year, but rather in the preparations that malicious actors are making today for a post-quantum reality.
Clark Alexander, co-founder and head of AI at Argentum AI, shared with Cointelegraph that he anticipates quantum computing will have “extremely limited commercial use” by 2026.
Crypto analyst Nic Puckrin, also a co-founder of Coin Bureau, was more straightforward. “The idea of a ‘quantum threat to Bitcoin’ is mostly marketing and only slightly a genuine risk… we are likely at least ten years away from computers capable of undermining existing cryptography,” he commented.
Why cryptocurrencies are at risk
Bitcoin (BTC) and major blockchain networks depend on public-key cryptography for wallet security and transaction authorization. Private keys sign transactions, public keys verify them, and hash functions secure the ledger. If a future quantum machine could extract private keys from public keys, the risk of massive fund theft becomes plausible.
Related: Willy Woo believes Bitcoin enthusiasts will purchase Satoshi’s stash if a quantum hack happens
This issue has reached US regulators as well. In September, a proposal was presented to the US Securities and Exchange Commission (SEC) warning that quantum computing could eventually dismantle the encryption securing Bitcoin and other digital assets.
Experts in cryptography agree that signatures represent the weakest point. “Any cryptographic system relying on a mathematical problem that Shor’s algorithm can efficiently solve (the difficulty of factoring large semiprimes) is at risk,” said Sofiia Kireieva, blockchain R&D specialist at Boosty Labs.
Related: Aptos introduces post-quantum signatures before urgency strikes
She further explained that if a quantum-capable adversary were to target Bitcoin or a similar blockchain, the elliptic curve digital signature algorithm (ECDSA) employed for private-public keys would be the “weakest link.” In contrast, SHA-256 hash functions show much less vulnerability. Grover’s algorithm might provide a quadratic speed-up at most, which can be countered by using larger hashes, according to Kireieva.
Ahmad Shadid, founder of the O Foundation in Switzerland, also stated that signatures are the primary vulnerability. “The most at-risk cryptographic component is the ECDSA digital signature algorithm, particularly concerning the safety of public/private key pairs used for transaction signing, especially with address reuse (increasing vulnerability),” he noted.
Related: Why Vitalik believes quantum computing could disrupt Ethereum’s cryptography sooner than anticipated
What experts expect in 2026
Despite rising worries, significant technical obstacles make a cryptographic failure by 2026 improbable.
Kireieva pointed out the physical limitations facing quantum hardware. “Current quantum devices possess only hundreds or thousands of noisy qubits, much less than needed to execute complex algorithms like Shor’s… This means a realistic cryptanalytic attack would require millions of physical qubits, ultra-low gate error rates, and the capability for millions of sequential operations without losing coherence,” she explained.
Kireieva added that this would necessitate breakthroughs in materials science, quantum control, fabrication, and signal isolation. “The limitation is not only technical — it is also rooted in the fundamental physics of our universe,” she asserted.
Alexander emphasized that not only is it unlikely for quantum computers to break Bitcoin’s encryption by 2026, but they may never do so under current methodologies. He argued that the true threat lies in advances in classical computing, which pose a more significant risk to encryption than quantum systems, suggesting that both quantum and traditional machines will need fundamentally new algorithms to genuinely compromise public-key cryptography.
Related: Adam Back: Bitcoin faces no quantum risk for the next 20–40 years
The “harvest now, decrypt later” problem
Currently, the real threat is not the breakdown of Bitcoin’s security in 2026, but rather that attackers are already gathering encrypted data.
“The likelihood of quantum threats materializing in 2026 is extremely low,” remarked Sean Ren, co-founder of Sahara AI, “but malicious actors are actively collecting as much encrypted data as they can… so when the technology matures, all that gathered data can be accessed.”
Leo Fan, co-founder of Cysic, supported this perspective, articulating that a common attack tactic is “harvest now, decrypt later,” where adversaries proactively accumulate sensitive encrypted data to unlock when quantum advancements occur.
Shadid explained that this leads to possible scenarios where terabytes of publicly accessible on-chain data could be harvested just to gather public keys, which quantum computers could later use to decipher private keys.
Related: What will happen to Satoshi’s 1M Bitcoin if quantum computing becomes a reality?
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, whose public keys have already been exposed on-chain, making them more prone to private-key recovery via a sufficiently capable quantum computer.
She recommended that users reduce their risk by refraining from address reuse, ensuring public keys stay concealed until funds are utilized, and preparing to transition to quantum-resistant wallets and address formats as soon as possible.
The crypto community has already initiated practical measures. In July, cryptography specialists proposed a method to substitute Bitcoin’s current signature frameworks with quantum-resistant options, indicating that roughly 25% of Bitcoin’s funds are currently vulnerable due to public keys being disclosed on-chain.
In November, Qastle announced plans to integrate quantum-grade security into hot wallets by enhancing the underlying cryptography. Instead of leveraging predictable software-based randomness, it employs quantum-generated randomness and post-quantum encryption to secure keys, transactions, and communications, all without necessitating added hardware or complex setups.
Related: IBM claims significant advancements toward quantum computers with new chips
The crypto sector does not face an immediate quantum apocalypse in 2026. However, discussions about the upcoming threat have shifted from “if” to “when.”
“The probability of a significant quantum attack… occurring by 2026 is low to moderate,” stated Fan. “Nevertheless, the chance that quantum technology becomes a leading risk factor in crypto security awareness by 2026… is high,” he added.
Magazine: Bitcoin vs. the quantum computer threat — Timeline and solutions (2025–2035)
