The G7 Cybersecurity Working Group is calling on countries and businesses to immediately begin transitioning to post-quantum cryptography. This warning is directly relevant to crypto networks, exchanges, and custodians, who need to undertake costly upgrades of their systems before quantum computers become a threat to modern cryptography.
The working group published a document on September 3, 2026, titled "Preparing for the Post-Quantum Era: A Call to Action," which frames quantum computing as a business and cybersecurity risk that organizations must be prepared for before the emergence of a cryptographically viable machine.
Why a report that nowhere mentions the word 'cryptocurrency' still strikes a blow at the crypto market
The G7 document contains no specific mentions of cryptocurrencies, although the concept is directly related to blockchain technology. Decrypt notes that cryptocurrency transactions and fund management are based on public-key cryptography.
While exact timelines are unknown, a number of recent advances suggest that in the future, quantum computers capable of breaking widely used public-key cryptography mechanisms will emerge.
— G7 Cybersecurity Working Group
The concern is not only about the possibility of future attacks.
Harvest now, decrypt later.
— G7 Cybersecurity Working Group
The strategy involves collecting encrypted data today and decrypting it in the future when quantum technology becomes sufficiently advanced. A similar problem exists with blockchains, where public keys and transaction history may remain visible forever, making keys vulnerable to future hacking.
The G7 proposes efforts in areas such as raising awareness, national policy, research, collaboration between public and private sectors, and post-quantum procurement requirements.
Europe has already put dates on the calendar
Europe has gone further by setting deadlines. In June 2025, the EU adopted a coordinated roadmap for transitioning to Post-Quantum Cryptography (PQC).
The European Commission's Post-Quantum Cryptography (PQC) policy insists that all member states begin transitioning to the new system by the end of 2026, while high-risk systems must transition immediately and by 2030.
This means quantum readiness has ceased to be merely a technical issue. As new requirements concerning post-quantum technology become part of procurement and cybersecurity legislation, companies without a proper migration policy may face compliance and competitiveness challenges.
Bitcoin and Ethereum take different paths
BIP-360 (Pay-to-Merkle-Root) is considered by Bitcoin as a soft fork proposal aimed at reducing vulnerability to long-term quantum computer attacks. BIP-360 requires the disabling of the Taproot key spending mechanism, which is susceptible to quantum processing, although its creators acknowledge that faster attacks on transactions in the mempool will still depend on the implementation of post-quantum digital signatures. The activation date for BIP-360 is not yet determined.
Ethereum is working on a broader post-quantum security system. In his roadmap update for February 2026, Vitalik Buterin mentioned four components that need upgrading: validator BLS signatures, KZG commitments, account ECDSA signatures, and application-layer zero-knowledge proofs. Ethereum plans to build the core post-quantum infrastructure in 2029, although the process of migrating to this new technology may take some additional time.
The cost is high. A compact secp256k1 ECDSA signature occupies about 64 bytes, while an older parameter set, Dilithium-5, used approximately 4595 bytes. The NIST-approved ML-DSA standard uses ML-DSA-87 signatures, which occupy about 4627 bytes. Thus, the signature size may also increase storage requirements, bandwidth, and transaction costs.
The short-term risk lies in the migration itself
Consequently, the immediate market risk is not about when a quantum computer will break Bitcoin. Rather, it's everything related to preparing for it: governance disputes, protocol development, larger key signatures, infrastructure changes, and old wallets whose public keys have been exposed.
An article published in March 2026 by Google Quantum AI argued that breaking 256-bit elliptic curve cryptography would require far fewer resources than previously thought. Google even announced the completion of its own systems migration by 2029.
NIST presented draft IR 8547, which recommends phasing out 112-bit ECDSA after 2030 and banning the use of ECDSA after 2035.
Previously, Cryptopolitan published a report claiming that quantum readiness may ultimately be incorporated into institutional custody criteria and investor due diligence standards, making a network's migration plan a competitive advantage.
