THE EU’S THREE FINANCIAL SUPERVISORS PUT QUANTUM IN THEIR AUTUMN RISK UPDATE — AN ADVANCED MACHINE COULD UNDERMINE WHAT SECURES BLOCKCHAINS, AND HARVEST NOW DECRYPT LATER MEANS THE CLOCK ALREADY STARTED

Three EU supervisors, the European Banking Authority, EIOPA and ESMA, published their autumn risk update on September 23. Document JC 2026 29. Inside it: “an advanced quantum computer could undermine some cryptography systems widely used to secure communications, transactions, databases and blockchains.”

The sentences after that are the ones that move the timeline. “Threats could materialise earlier than any viable commercial application. Currently-gathered information could be decrypted in the future (‘harvest now, decrypt later’).” Read that against bitcoin. An address that has ever spent has published its public key, and it sits on a ledger nobody can take down. There is no harvesting step left to do. The material was collected the moment it was broadcast, permanently, by design.

So separate the two halves. Checkable: the exposed keys, on chain, countable by anyone who wants to count them. Trusted: that a migration lands before the machine does. BIP-361, drafted by Jameson Lopp and five others, would phase out the signature types in use now and restrict spending from unmigrated funds five years after activation. It has not been adopted. Ethereum’s foundation is aiming at December 2029. The EU paper names no date for anyone, it just tells firms to start, and points at DORA’s requirement to use state of the art cryptography.

One more line from the same document, a few tables over: only 8 percent of crypto trades against the euro, against 40 to 50 percent for the dollar, and no EU-headquartered exchange in the top 15. The supervisors writing this warning are describing a market they largely do not host. The warning is still correct. At the time of this writing, bitcoin was $85,252.