The cryptocurrency world is taking a hard look at one of its most serious long-term threats: quantum computing. As advances in the technology accelerate, concerns are mounting that quantum machines could one day break the encryption systems that keep digital transactions and wallets secure.
Unlike today’s conventional computers, quantum computers are capable of solving extraordinarily complex mathematical problems at much greater speeds. That capability could potentially be used to unravel the cryptographic methods that protect the $2 trillion global cryptocurrency market — a market that already has a troubled history with major hacks.
While quantum computing is still largely in the experimental phase, alarm bells have grown louder since March, when research from Alphabet’s Google suggested the technology could break existing encryption sooner than anyone had anticipated. Google has indicated that quantum computers powerful enough to crack encryption could emerge as early as 2029 — a timeline far shorter than the decade-plus window that had previously been assumed.
Research from Citigroup and other institutions has reached similar conclusions, finding that quantum computing advances — combined with breakthroughs in artificial intelligence — have dramatically shortened the window before cryptocurrencies become broadly vulnerable to hackers.
Recognizing the risks to both the public and private sectors, U.S. President Donald Trump last month signed executive orders aimed at strengthening America’s quantum computing capabilities.
Some crypto companies and blockchain developers are already working on plans to upgrade their networks with quantum-resistant encryption — a process that experts say could take years and require sweeping changes to the entire digital asset infrastructure.
“It’s the most direct and existential threat towards cryptocurrencies and crypto networks,” said Chris Tam, head of quantum innovation at BTQ Technologies, a firm focused on quantum security.
At the heart of the vulnerability is the cryptography that most blockchains rely on. The majority use decades-old elliptic-curve cryptography to generate the public and private keys and digital signatures that verify ownership of crypto assets and authorize transactions. Public keys are mathematically derived from private keys and, in many blockchain networks, become visible to the public once assets are used or transferred.
While today’s computers cannot realistically reverse-engineer a private key from a public one, a sufficiently powerful quantum computer could — potentially allowing hackers to forge digital signatures and push through fraudulent transactions.
The risk is especially serious for public crypto networks, where transactions — unlike traditional bank payments — cannot be reversed.
“Crypto especially is uniquely exposed because blockchains are transparent and permanent,” said Utkarsh Ahuja, managing partner at Moon Pursuit Capital, a crypto investment firm.
Bitcoin, the world’s largest cryptocurrency, is considered especially at risk. Its 17-year transaction history has created a large pool of publicly visible keys. According to an unpublished June 2026 working paper by independent researcher Ahmed Raza Muhammad Umer, roughly 35% of Bitcoin’s circulating supply could be exposed to a quantum attack. Other research from last year put that figure as high as 50%.
Even a single incident in which a hacker steals and offloads a large amount of a token could devastate its price, warned Cristiano Ventricelli, vice president and senior analyst of digital assets at Moody’s Ratings. “Everyone will feel the impact,” he said.
That concern has already influenced some investment decisions. Christopher Wood, the widely followed global head of equity strategy at Jefferies, removed a 10% Bitcoin allocation from his model portfolio in his January newsletter, citing the long-term “existential” threat posed by quantum computing.
Despite the warnings, many in the industry believe there is still time to act. Ahuja and others said they expect it will be a few more years before quantum computing can actually crack blockchain encryption, and that the industry can transition to new “post-quantum” cryptography in the meantime.
However, crypto executives caution that moving too quickly carries its own risks, since post-quantum cryptography is still evolving rapidly. Post-quantum digital signatures are generally much larger than traditional ones, which increases storage and bandwidth demands. That could drive up costs and hurt the user experience — particularly on blockchains with fixed block-size limits, such as Bitcoin, according to Zach Pandl, head of research at crypto asset manager Grayscale. Still, Pandl expressed confidence that the industry would ultimately find solutions.
“There is an engineering challenge ahead, but there are engineering solutions already on the table,” he said.
One senior cybersecurity executive at a major crypto company said he expects it will take his firm two years to become fully quantum-resistant. Several people in the industry compared the scope of the effort to the Y2K overhaul, during which more than $300 billion was spent worldwide to fix the so-called “millennium bug.”
The challenge is particularly complicated for blockchains, which are mostly decentralized and governed by broad communities that may struggle to reach consensus on a course of action, said Tam of BTQ Technologies.
As of now, none of the top 20 blockchains have put a post-quantum signature algorithm in place, according to people interviewed for this story. In Bitcoin’s case, developers and market participants remain divided on which solution to adopt and when. The Ethereum Foundation, which backs the blockchain underlying ether — the second-largest cryptocurrency — has set a target of 2029 to achieve full protection against quantum threats.
“The sort of disaster scenario is that it happens way sooner than we think,” said Christopher Smith, CEO of Quantus, a blockchain that has already adopted post-quantum cryptography.
Among the early movers is the Algorand Foundation, which supports the Algorand blockchain. The foundation’s native token carries a market capitalization of around $780 million. Last month, the foundation published a post-quantum roadmap and announced plans to begin supporting post-quantum accounts later this year, said Bruno Martins, the foundation’s chief technology officer.
“It felt right to start doing (something) now, because it’s responsible to have a plan,” Martins said.
