G7 Warns Quantum Computers Threaten Current Crypto

G7 finance ministers and central bank officials warned that advances in quantum computing could break widely used cryptography and urged governments, industry and standards bodies to accelerate preparations. The statement was released this week.

The group called for inventories of vulnerable cryptographic systems, plans to transition to quantum-resistant algorithms, and international cooperation on technical standards and timelines to guide migration efforts.

Quantum computers large enough to run certain algorithms can solve the mathematical problems that secure RSA and elliptic-curve cryptography. Those public-key systems protect online communications, software updates and controls for cryptocurrency wallets. If a sufficiently powerful quantum computer appears, an attacker could reconstruct private keys or forge signatures, exposing past and future transactions to theft or manipulation.

Cryptocurrency firms and custodians are evaluating technical options to reduce risk. Measures under consideration include adopting post-quantum signature schemes, implementing hybrid signatures that combine classical and quantum-resistant algorithms, increasing use of multi-signature and threshold signing techniques, rotating keys more frequently, and moving high-value holdings into cold storage while upgrades are tested. Several firms are testing new cryptographic libraries and working with experts to develop migration plans.

National and international standards bodies are evaluating post-quantum cryptographic algorithms. The G7 urged accelerated adoption once standards are finalized and requested clear guidance on timelines and interoperability so software and hardware vendors can design systems that can switch algorithms without exposing keys.

Transitioning presents technical and operational challenges for distributed ledgers and existing wallets. Many blockchains reveal public keys when addresses are spent or when signatures are broadcast, which can leave past transactions vulnerable if signatures can later be forged. Upgrading protocols across decentralized networks requires coordinated software updates, careful key migration to avoid exposing private keys, and mechanisms to preserve backward compatibility. Industry participants cautioned that poorly executed migrations could introduce new vulnerabilities.

Centralized custodians can update software and migrate keys in a controlled environment. Decentralized systems depend on broad user adoption of upgraded client software. Smaller firms and individual holders face practical hurdles in updating wallets and managing key transitions securely.

Post-quantum cryptography refers to algorithms believed to resist attacks by both quantum and classical computers. The U.S. National Institute of Standards and Technology and other agencies have evaluated candidate algorithms and are moving toward standardization. The G7 and industry actors emphasized early assessment and planning because the exact timeline for when quantum machines will pose a concrete threat remains uncertain.

The statement read, “Governments, industry and standards bodies should accelerate preparations to defend sensitive systems against future quantum attacks.”