EU watchdogs say quantum threat to crypto may come sooner
Europe's three financial supervisors flagged quantum risk in their autumn report. By some estimates, about 6.9 million BTC sit in addresses with exposed keys.
Europe's financial regulators think the quantum threat to encryption may not wait for quantum computers to become commercially useful. That warning appears in the Autumn 2026 Risk and Vulnerabilities report of the Joint Committee of the European Supervisory Authorities, the body that links the EU's banking regulator (EBA), its securities and markets authority (ESMA) and its insurance and pensions authority (EIOPA). The three have now added quantum computing to their list of near-term risks for the financial system.
A risk that may arrive early
The supervisors' concern is that powerful quantum machines could crack the cryptography used to secure communications, payments, databases and blockchains. Crucially, they said this could materialise earlier than any viable commercial application of the technology, so a working attack would not require quantum computers to be widely available.
They also pointed to harvest now, decrypt later tactics. Here, attackers copy encrypted data today and simply store it until they have the tools to unlock it. Brussels is already pushing for action: the European Commission wants member states to start migrating to post-quantum cryptography by the end of 2026 and to have high-risk systems protected by 2030.
Which bitcoins are most at risk
Not every coin is equally exposed. A Bitcoin address reveals its public key once it has been used to send funds, and some older address formats show it from the start. By some estimates, around 6.9 million BTC, with a value of about $586 billion, now sit in addresses where the public key is already public, chiefly legacy formats and reused addresses. Those coins would be the first targets for a capable quantum attacker. Coins held in newer addresses that have never sent a transaction are better shielded, because their public key stays hidden until they are spent.
The Bitcoin community is working on solutions. In one recent example, a contest run by StarkWare, in which entrants used AI coding tools, cut the estimated cost of a quantum-safe Bitcoin transaction from about $320 to $66 in just one week. That remains expensive for everyday use, but the trend is sharply downward.
What Indian holders should do
Keep this in perspective: no quantum computer known today can forge Bitcoin signatures. Still, a few simple habits make your coins less exposed. Avoid sending from and receiving to the same address repeatedly, choose a modern wallet that gives you a fresh address for every incoming payment, and watch for guidance from your wallet provider if Bitcoin moves to post-quantum address types. If your holdings sit on an exchange, the exchange controls the private keys, so it is worth understanding how that platform keeps customer funds secure.
This article is AI-assisted, educational and general in nature. It is not financial advice and never a guarantee of profit. Every trade is at your own risk on your own exchange. See our risk disclosure and editorial policy.
