The cryptocurrency industry has begun preparing for quantum computing threats that could break encryption protecting digital wallets and blockchain transactions, according to Reuters. Google research published in March suggested quantum machines capable of attacking current cryptography may arrive sooner than earlier estimates. The concern has intensified as governments and technology companies increase quantum computing investment, with the field now tied to national security, cyber defense, and the technology competition between the United States and China.
Quantum computers are designed to solve certain mathematical problems far faster than conventional computers. Most major blockchains rely on 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.
Bitcoin Faces Significant Exposure to Quantum Attacks
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About 35% of Bitcoin's circulating supply could be exposed to a quantum attack, according to an unpublished June 2026 working paper cited by Reuters. 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 Accelerates Industry Migration Timeline
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.
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.
Trump Administration Issues Quantum Computing Executive Orders
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.
Ethereum Foundation Targets 2029 for Quantum Protection
Crypto firms and blockchain developers are working on plans to shift networks to post-quantum cryptography. Reuters reported that none of the top 20 blockchains has implemented a post-quantum signature algorithm, according to people interviewed for its story.
The Ethereum Foundation is targeting 2029 for full protection from quantum computing. The Algorand Foundation has published a post-quantum roadmap and plans to support post-quantum accounts later this year.
Technical Challenges Complicate Bitcoin Upgrade Path
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.
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.
One senior cybersecurity executive at a major crypto company said that his firm expects it will take two years to become fully quantum-resistant. Industry executives compared the work ahead to the Y2K overhaul, when governments and companies spent heavily to update older systems before the year 2000.
FAQ
What did Google Research announce about quantum computing threats to cryptocurrency?
Google Research said in March that future quantum computers may be able to break the elliptic-curve cryptography used by cryptocurrency systems with fewer resources than previously understood. The company is working toward a 2029 migration timeline for most of its authentication and digital signature systems.
How much Bitcoin is exposed to quantum computing attacks?
About 35% of Bitcoin's circulating supply could be exposed to a quantum attack, according to an unpublished June 2026 working paper cited by Reuters. Other research has placed the estimate as high as 50%. A Deloitte analysis said more than 4 million Bitcoin, or about 25% of supply at the time of its study, was potentially vulnerable.
When does Ethereum plan to achieve quantum protection?
The Ethereum Foundation is targeting 2029 for full protection from quantum computing. The Algorand Foundation plans to support post-quantum accounts later this year.
