Quantum computing has long been perceived as a potential danger to cryptocurrencies, with the capability to eventually breach the cryptography that protects Bitcoin and other blockchains. As 2026 approaches, this concern is being reignited as leading tech companies ramp up their quantum research and funding.
While the technology is not yet primed for broad application, the momentum behind investment and experimentation is increasing. In February, Microsoft introduced its Majorana 1 chip, touted as “the world’s first quantum chip with a new Topological Core architecture,” sparking discussions about the speed at which quantum hardware may transition from research to practical applications.
Nevertheless, most experts maintain that the threat to cryptocurrency remains theoretical at this stage. They contend that the pressing issue is not an immediate cryptographic breakdown in the coming year, but rather the preparations some attackers are undertaking today for a post-quantum world.
Clark Alexander, co-founder and AI lead at Argentum AI, shared with Cointelegraph his belief that quantum computing will have “extremely limited commercial viability” by 2026.
Nic Puckrin, cryptocurrency analyst and co-founder of Coin Bureau, was more direct: “The narrative of a ‘quantum threat to Bitcoin’ is 90% marketing and 10% immediate concern… we are most likely at least ten years away from computers capable of breaking current cryptography,” he stated.
Why cryptocurrencies are vulnerable
Bitcoin (BTC) and many major blockchain networks utilize public-key cryptography to secure wallets and authorize transactions. Private keys are used to sign transactions, while public keys verify them, and hash functions protect the ledger. Should a future quantum machine be able to derive private keys from public keys, it could lead to substantial theft of funds.
Related: Willy Woo anticipates Bitcoin enthusiasts will purchase Satoshi’s stash if a quantum breach occurs
The potential issue has garnered the attention of US regulators as well. In September, the US Securities and Exchange Commission (SEC)’s cryptocurrency task force reviewed a proposal cautioning that quantum computing could ultimately undermine the encryption safeguarding Bitcoin and other digital assets.
From a technical perspective, there is consensus among cryptographers that signatures present the weakest point. “Any cryptographic framework whose security hinges on a mathematical challenge that Shor’s algorithm can efficiently resolve (the difficulty of factoring large semiprimes),” remarked Sofiia Kireieva, blockchain R&D and subject-matter expert at Boosty Labs.
Related: Aptos presents post-quantum signatures before they become critical
She further explained that if a quantum-capable adversary targets Bitcoin or a comparable blockchain, the elliptic curve digital signature algorithm (ECDSA) used for public-private key pairs would be the “weak link.” On the other hand, SHA-256 hash functions are considerably more robust. Grover’s algorithm would provide at most a quadratic speed-up, which can be countered by utilizing larger hashes, according to Kireieva.
Ahmad Shadid, founder of the Switzerland-based O Foundation, also identified signatures as the foundational vulnerability. “The most susceptible cryptographic element is the ECDSA digital signature algorithm, particularly regarding the security of public/private key pairs used to sign transactions, especially with address reuse (this significantly heightens vulnerability),” he noted.
Related: Why Vitalik believes quantum computing could threaten Ethereum’s cryptography sooner than anticipated
Expert predictions for 2026
Despite increasing apprehension, significant technical obstacles render a cryptographic breakdown by 2026 improbable.
Kireieva highlighted the physical limitations facing quantum hardware. “Current quantum devices possess only hundreds or thousands of noisy qubits, which is far from what is necessary to execute deep algorithms like Shor’s… This implies that a viable cryptanalytic assault would require millions of physical qubits, ultra-low gate error rates, and the capacity to conduct millions of sequential operations without losing coherence,” she remarked.
Kireieva added that achieving this would also necessitate breakthroughs in materials science, quantum control, fabrication, and signal isolation. “The bottleneck is not solely engineering—it involves the fundamental physics of the universe,” she elaborated.
Alexander pushed this point further, suggesting that quantum computers are not only unlikely to crack Bitcoin’s encryption by 2026 but may also never succeed under current methodologies. He asserted that the true threat is elsewhere, arguing that improvements in classical computing are a greater danger to encryption than quantum systems, indicating that both quantum and conventional machines would need radically new algorithms before public-key cryptography could be feasibly compromised.
Related: Adam Back: Bitcoin faces no quantum risk for the next 20–40 years
The “harvest now, decrypt later” dilemma
In the meantime, the pressing concern in 2026 is not that Bitcoin will fail; rather, it is that attackers are already amassing data.
“A genuine quantum threat manifesting in 2026 is highly unlikely,” stated Sean Ren, co-founder of Sahara AI, “but malicious actors are actively gathering as much encrypted data as possible… so that when the technology is mature, all that archived information will become decipherable.”
Leo Fan, co-founder of Cysic, echoed this sentiment, noting that a common attack strategy is “harvest now, decrypt later,” where adversaries gather sensitive encrypted data for eventual decryption once quantum advancements are achieved.
Shadid elaborated on this by explaining that someone could be downloading large volumes of this publicly available on-chain data simply to gather public keys, which could later be utilized with a quantum computer to decrypt private keys.
Related: What will happen to Satoshi’s 1M Bitcoin if quantum computers become operational?
Millions of Bitcoin remain vulnerable: How is crypto adapting?
Kireieva estimated that 25%–30% of all BTC (approximately 4 million coins) are held in addresses that are vulnerable—public keys that have already been exposed on-chain, increasing the risk of private-key recovery by a sufficiently advanced quantum computer.
She recommended that users limit their exposure by refraining from address reuse, keeping public keys concealed until funds are utilized, and being ready to switch to quantum-resistant wallets and address formats as soon as they become available.
The cryptocurrency community has also initiated practical measures. In July, cryptography experts put forth a plan to substitute Bitcoin’s current signature systems with quantum-resistant alternatives, highlighting that about a quarter of Bitcoin’s funds are already exposed due to public keys being disclosed on-chain.
In November, Qastle announced initiatives to provide quantum-grade security for hot wallets by enhancing the underlying cryptography. Rather than depending on predictable software-driven randomness, it utilizes quantum-generated randomness and post-quantum encryption to fortify keys, transactions, and communications, all without the need for additional hardware or complex setups.
Related: IBM claims significant progress toward quantum computers with new chips
The crypto sector does not face an imminent quantum crisis in 2026. Nonetheless, discussions surrounding the threat are shifting from “if” to “when.”
“The probability of a major quantum assault… occurring by 2026 is low-to-moderate,” Fan remarked. “However, the likelihood that quantum technology becomes a critical risk factor for crypto security awareness in 2026… is high,” he concluded.
Magazine: Bitcoin vs. the quantum computer threat — Timeline and solutions (2025–2035)
