MilestoneTheory & algorithmsConfirmed
Google researcher estimates RSA-2048 could be broken with under a million qubits
May 2025
Craig Gidney of Google Quantum AI estimates that a quantum computer with fewer than a million noisy qubits could factor a 2048-bit RSA key in less than a week, 20 times fewer qubits than his 2019 estimate of 20 million. No existing machine comes close to these requirements.
Why it matters
RSA-2048 is a common standard for securing online data, so a lower cost estimate strengthens the case for moving to post-quantum encryption soon.
Craig Gidney · Google
Related
- NIST publishes the first post-quantum encryption standards (Aug 13, 2024)
Sources (3)
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arXiv (Craig Gidney)
How to factor 2048 bit RSA integers with less than a million noisy qubits
“I estimate that a 2048 bit RSA integer could be factored in less than a week by a quantum computer with less than a million noisy qubits.”
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Google Security Blog
Tracking the Cost of Quantum Factoring
“Yesterday, we published a preprint demonstrating that 2048-bit RSA encryption could theoretically be broken by a quantum computer with 1 million noisy qubits running for one week. This is a 20-fold decrease in the number of qubits from our previous estimate, published in 2019.”
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The Quantum Insider
Google Researcher Lowers Quantum Bar to Crack RSA Encryption
“Despite the reduced threshold, no existing quantum computer can meet the performance requirements, which include five days of continuous operation with fast, low-error cycles.”
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