Bitcoin Quantum Threat Inches Closer as IBM Claims 'Trusted Quantum Advantage'

IBM says it has demonstrated what it calls “trusted quantum advantage,” claiming a quantum computer completed a computation beyond the reach of leading classical simulation methods while also providing statistical evidence that the result was accurate.

According to IBM, the work, conducted with researchers at the University of Chicago, is the latest milestone in the company’s effort to build fault-tolerant quantum computers. The experiment does not materially change Bitcoin’s near-term security outlook. Still, it adds to a growing body of research aimed at overcoming one of quantum computing’s biggest obstacles: reliably correcting errors while scaling to larger systems.

Quantum advantage refers to any milestone where a quantum computer solves a practical problem faster, cheaper, or more efficiently than the best possible classical computer.

“We are now firmly in the quantum advantage era,” Director of IBM Research and IBM Fellow Jay Gambetta said in a statement. “This milestone gives scientists, developers, and businesses a new foundation for trusting quantum computers as they scale to problems far beyond what we can achieve classically.”

In its latest announcement, IBM said researchers encoded 70 logical qubits using a new error-correction technique, completing a computation in roughly 15 minutes that IBM says would require impractical amounts of time using today’s leading classical simulation methods. The experiment executed 2,415 logical two-qubit operations and 468 logical T gates, while reducing logical error rates to about one-tenth of the underlying physical error rate.

IBM says the experiment also addresses a longstanding criticism of quantum advantage demonstrations: verification. Instead of relying on traditional random circuit sampling, the researchers developed a structured alternative that allows errors to be detected during computation while preserving the mathematical difficulty of the problem.

“Verification remains one of the biggest challenges in firmly establishing experimental quantum advantage,” Associate Professor at the University of Chicago, Bill Fefferman, added. “This experiment develops techniques to better characterize the fidelity of hard quantum states under noise, increasing confidence that the quantum computer is solving a computationally hard problem.”

The announcement follows several milestones IBM laid out in its Starling roadmap. Released last June, the roadmap targets a large-scale fault-tolerant quantum computer by 2029. The roadmap calls for verified quantum advantage demonstrations before scaling to modular processors and, ultimately, a system capable of roughly 200 logical qubits and 100 million quantum operations.

Over the past year, IBM has continued to build toward those goals.

In October 2025, researchers demonstrated a 120-qubit GHZ “cat state,” followed a month later by the introduction of its 120-qubit Nighthawk processor and experimental Loon chip, both designed to advance fault-tolerant computing. Earlier this year, the company expanded public access to more advanced quantum hardware, giving researchers additional time to develop algorithms and error-correction techniques.

For Bitcoin, the latest experiment is better viewed as an incremental technical advance towards ‘Q-Day’ than a change in the threat landscape. Bitcoin relies on elliptic curve cryptography for digital signatures, and researchers generally estimate that breaking the network’s encryption would require thousands of logical qubits operating on a fault-tolerant quantum computer—far beyond the 70 logical qubits demonstrated in IBM’s latest experiment.