The race to secure digital assets is gaining urgency as governments and technology companies pour money into quantum computing, a field now tied closely to national security, cyber defense, financial infrastructure, and the wider technology competition between the United States and China.
The cryptocurrency industry has begun preparing for the risk that quantum computers may one day break the encryption used to protect digital wallets and blockchain transactions, Reuters reported. The concern has grown since March research from Google suggested that quantum machines capable of attacking current cryptography may arrive sooner than earlier estimates.
Quantum computers are designed to solve certain mathematical problems far faster than conventional computers. That matters for crypto because most major blockchains rely on older public-key cryptography to verify ownership and authorize transactions. If a powerful quantum computer derived a private key from a visible public key, an attacker could sign transactions and move assets without the owner's permission.
Most blockchains use elliptic-curve cryptography for public and private keys. Public keys are often revealed once a wallet is used in a transaction. Bitcoin is seen as especially exposed because its 17-year transaction history has left many public keys visible on-chain.
About 35% of Bitcoin's circulating supply could be exposed to a quantum attack, according to an unpublished June 2026 working paper cited by the outlet. Other research has placed the estimate as high as 50%. A separate Deloitte analysis said more than 4 million Bitcoin, or about 25% of supply at the time of its study, was potentially vulnerable because of exposed public keys and address reuse.
The risk is not limited to crypto, but public blockchains have specific challenges. Transactions are transparent, permanent, and generally irreversible.
Google Research said future quantum computers may be able to break the elliptic-curve cryptography used by cryptocurrency systems with fewer resources than previously understood. The company said it is working toward a 2029 migration timeline for most of its authentication and digital signature systems and urged the cryptocurrency community to move toward post-quantum cryptography.
The issue has also become a policy concern. President Donald Trump issued executive orders last month aimed at strengthening U.S. quantum capability, Reuters reported. The move followed growing attention from government agencies and companies that see quantum computing as both a strategic technology and a cybersecurity risk.
Financial institutions are also studying the issue. Citigroup said in a March analysis that quantum computing mainly threatens public-key cryptography, especially the digital signatures used for authentication, identity, and blockchain ownership. Citi said the most immediate blockchain risk is exposed public keys and operational key infrastructure, rather than the basic blockchain protocol itself.
Crypto firms and blockchain developers are now working on plans to shift networks to post-quantum cryptography, though that process is complex. Reuters reported that none of the top 20 blockchains has implemented a post-quantum signature algorithm, according to people interviewed for its story.
Ethereum has started mapping out its own transition. The Ethereum Foundation is targeting 2029 for full protection from quantum computing. The Algorand Foundation has also published a post-quantum roadmap and plans to support post-quantum accounts later this year.
Bitcoin faces a more difficult path because its development process is decentralized and community-driven. Developers and market participants remain divided over which technical fix to adopt and when to move. Any upgrade would require agreement across developers, miners, exchanges, custodians, wallet providers, and users.
Some analysts have urged caution over framing the issue as an immediate crisis. Bernstein analysts said the quantum threat to Bitcoin is "neither existential, nor novel," DL News reported, adding that the issue is part of a broader technology upgrade cycle. The firm also said crypto networks need to prepare because migration takes time.
Moving too early also carries risks. Post-quantum digital signatures are generally larger than current signatures, which can increase storage and bandwidth demands. Zach Pandl, head of research at Grayscale, told Reuters that those changes could raise costs and affect user experience, especially on blockchains with fixed block-size limits such as Bitcoin.
Industry executives compared the work ahead to the Y2K overhaul, when governments and companies spent heavily to update older systems before the year 2000. One senior cybersecurity executive at a major crypto company said that his firm expects it will take two years to become fully quantum-resistant.
