IonQ Publishes Architecture to Break secp256k1 with Shor’s Algorithm

On September 8, 2026, IonQ published their end-to-end architecture for breaking secp256k1. While we have estimated that ECC-256 would be cracked in 2028, this is the first fully compiled, end-to-end architecture and blueprint from a quantum computing company to provide a pathway to do so. Their approach would require just under 20,000 physical qubits and ~1,450 logical qubits, use Shor’s Algorithm, and require nearly 26 days of wall clock time.

secp256k1 is an elliptic curve cryptographic method primarily used in blockchain and cryptocurrency services. Notably, Bitcoin and Ethereum use it in signing or authorizing transactions at the wallet level. It is not used in mining operations. It is not as common in internet or web cryptography. You can read more about it on Ledger’s website.

While this is a new development, this does not change our estimates of when Q-Day arrives. It substantiates the existing June 10, 2028 date we have published.

If you have read our other notes you will have noticed that we believe acceleration is a key trait in quantum computing. Generally, first 2035, then 2030 were viewed as likely years when cryptographic methods would be cracked. We chose 2028 because we strongly believe that acceleration is more likely than not with this frontier technology. While IonQ’s paper is theoretical – it hasn’t been run on an actual computer and actually cracked secp256k1 – we believe that their approach will play out. Of course, keep in mind that more acceleration is possible and this date could arrive earlier.