On September 8, 2026, IonQ published an estimate of the resources needed for a quantum attack on secp256k1 cryptography, which underpins Bitcoin. According to the company, a fault-tolerant quantum computer with roughly 20,000 physical qubits would need about 26 days to break this crypto scheme.

What IonQ Actually Measured

IonQ calls this the first end-to-end, fault-tolerant resource estimate for running Shor’s algorithm. The team used their IonQ Walking Cat architecture to show how a real-world application could be optimized for an ion-trap quantum computer with error correction. The result: concrete parameters for a hypothetical attack—how many physical qubits you’d need and a ballpark figure for how long it would take.

Why This Matters for Bitcoin

The numbers IonQ shared specifically target secp256k1 cryptography. The company lays out the conditions and resources a fault-tolerant quantum computer would need to pull off such an attack. This is a theoretical resource estimate—not a report of an actual exploit.

$8.18M Quantum Defense Contract

At the same time, IonQ announced an $8.18 million contract focused on protecting corporate data from quantum attacks. Details of the deal haven’t been disclosed.