As estimates for “Q-Day” continue to approach, experts warn that crypto’s biggest hurdle in defending against quantum attacks may not be its encryption technology, but its slow and complex governance process.
Quantum computing threatens every encrypted system around the world, including those operated by major banks and financial institutions. However, cryptocurrencies could be among the first technologies to face a real-world quantum challenge because of their decentralized architecture.
Eddy Zervigon, CEO of Quantum Xchange, said crypto could act as the “canary in the coal mine” for quantum-related threats. His company develops security solutions designed to protect networks, including financial infrastructure, from quantum-powered attacks. He believes cryptocurrencies are likely to be targeted first because of their decentralized nature.
According to Zervigon, a successful attack on a cryptocurrency network would indicate that someone has developed a cryptographically relevant quantum computer capable of breaking today’s encryption standards.
A quantum computer powerful enough to crack the elliptic-curve cryptography behind Bitcoin’s signatures and the encryption used by traditional financial systems has not yet been created. However, experts say the timeline for such technology is becoming shorter.
Zervigon noted that companies investing billions in quantum research, including Microsoft and IBM, generally expect a commercially viable, cryptographically capable quantum computer could arrive around 2029. He said the estimate is based on comments from industry leaders rather than speculation.
Recent breakthroughs have reinforced those expectations. Google researchers found that breaking the elliptic-curve cryptography protecting major cryptocurrencies like bitcoin and ether may require fewer than 500,000 physical qubits, significantly lower than earlier estimates. The development has led some observers to move their Q-Day forecasts closer to 2029.
Governments are also preparing for the transition. The U.S. administration has set goals to develop advanced quantum computing capabilities by 2028 and move critical assets and federal data systems to post-quantum cryptography by 2030.
Despite advances in quantum-resistant technology, experts say crypto’s main weakness may lie in its governance model. Unlike traditional financial institutions, which can upgrade systems through centralized decisions, decentralized blockchains require broad agreement from a global network of participants.
Deutsche Digital Assets highlighted governance speed as the major difference between traditional finance and decentralized networks. Large banks can approve security upgrades through internal processes, while public blockchains may require coordination among millions of users, developers, and stakeholders.
Bitcoin’s history shows how difficult that process can be. Major upgrades, including the 2017 SegWit change, faced strong opposition within the community and eventually contributed to blockchain splits that created networks such as Bitcoin Cash and Bitcoin Gold.
The key issue is not whether post-quantum cryptography will be available, but whether Bitcoin and other decentralized networks can reach consensus quickly enough to implement those protections.
Experts also caution that Q-Day should not be viewed as a single moment when encryption suddenly fails. Instead, the threat could emerge gradually as attackers collect encrypted information today and decrypt it later when quantum technology becomes powerful enough.
Zervigon explained that attackers do not need to break encryption instantly to cause damage. If they can unlock valuable data within months while it still has economic or strategic value, the attack can still succeed.
This means the quantum threat could become relevant before computers are capable of instantly compromising blockchain transactions, making timely preparation and upgrades essential.
