---
id: "2026-11-06-deepmind-ai-agents-rsa-1024-cryptanalysis"
url: "https://postcutoff.com/e/2026-11-06-deepmind-ai-agents-rsa-1024-cryptanalysis/"
as_of: "2026-11-09T21:13:00+01:00"
date: "2026-11-06"
date_precision: day
category: research
importance: 4
confidence: high
status: [Confirmed]
sources: 4
editor: human editor
human_review: null
version: "2026-11-08"
---

As of: 2026-11-09 21:13 CET.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/e/2026-11-06-deepmind-ai-agents-rsa-1024-cryptanalysis/

# Google DeepMind: human-guided AI agents find two new weaknesses in legacy 1024-bit RSA

Full title: Google DeepMind: human-guided AI agents find two new weaknesses in legacy 1024-bit RSA (signature forgery and batch factoring)

On Nov 6, 2026 Google DeepMind published two technical papers in which AI agents, supervised by researchers and co-authored with cryptographers Nadia Heninger and Emmanuel Thomé, found cheaper attacks on obsolete 1024-bit RSA: a result on when padding stops protecting signatures against chosen-input forgery, and a batch number-field-sieve algorithm that cuts the per-key cost of factoring many 1024-bit keys by about 30x. No key was broken in practice and DeepMind says 2048-bit RSA is unaffected.

## Key facts
- Scope stated by DeepMind: 'these results only affect obsolete 1024-bit RSA systems'; modern protocols using 2048-bit or larger keys 'remain secure'
- Signatures: once an attacker controls roughly half or more of the signed block, padding adds no protection against forgery (chosen inputs to a signing device)
- Demonstration in a sandbox on an already-factored 1024-bit benchmark key from an earlier academic study: forgery reproduced with 3.5x less CPU time than the prior method, under 1/1000 of the cost of factoring the key
- For short controlled inputs (e.g. a 32-byte hash) a new algorithm improves on the previous best by ~1,600x for 1024-bit keys — a theoretical estimate, not run
- Batch factoring: new algorithm with better asymptotic complexity ('factorization factories', batch NFS), ~30x lower average cost per additional 1024-bit key versus previous batch methods
- Led by Dj Dvijotham and Abhradeep Thakurta (DeepMind Science), with Nadia Heninger (UC San Diego, Inria) and Emmanuel Thomé (Inria); announced by VP Science Pushmeet Kohli in an X Article
- Papers are PDFs on DeepMind's storage, not peer-reviewed at announcement; the role split between agents and humans is described only as 'guided by humans'

## What happened

Google DeepMind's Science team announced on Nov 6, 2026 (X post and an X Article by Pushmeet Kohli) that AI agents
"guided by human supervision" uncovered "two major weaknesses on legacy 1024-bit RSA-based cryptosystems, showing that
these systems can be compromised with a lower computational budget than previously thought possible." Details are in two
technical papers linked from the article. Viral summaries (e.g. "Google breaks RSA keys") overstate it: no new key was
factored; the forgery demo used a key already factored in earlier work, and the 1,600x and 30x figures are cost estimates.

## Why it matters

Another lab result (after Anthropic's July cryptanalysis work) arguing that AI agents can shift cryptographic hardness
estimates faster than the usual years-long cadence; DeepMind frames it as a reason for proactive stress-testing.

## Your AI and this story

- GPT-6 Astra (training cutoff April 2026): 190 days after its cutoff
- Claude Opus 5.5 (training cutoff June 2026): 129 days after its cutoff
- Gemini 4 Argon (training cutoff March 2026): 220 days after its cutoff
- Grok 4.7 (training cutoff May 2026): 159 days after its cutoff

## Sources

1. [Pushmeet Kohli (X Article): Advancing the frontier of cryptanalysis](https://x.com/pushmeet/status/2118752095859794390) (x.com, official)
2. [Google DeepMind on X (136k views)](https://x.com/GoogleDeepMind/status/2118755418675765656) (x.com, official)
3. [Paper: Faster affine root and a 1024-bit computation (signatures)](https://storage.googleapis.com/deepmind-media/papers/Faster_Affine_Root_and_a_1024bit%20Computation.pdf) (storage.googleapis.com, paper)
4. [Paper: Multiple number fields in factorization factories and batch NFS](https://storage.googleapis.com/deepmind-media/papers/Fan_Factories_Multiple_Number_Fields_in_Factorization_Factories_and_Batch_NFS.pdf) (storage.googleapis.com, paper)

## Changes

- 2026-11-08 (filed): Created (missed on 11-07)

## Related

- 2026-10-29: [Deterministic factoring in N^o(1) steps, Lean-checked, ideas by Claude](https://postcutoff.com/e/2026-10-29-deterministic-factoring-n-o1-lean-claude-rudich-rousseau/index.md)
- 2026-10-07: [After OpenAI's math release, Justin Drake urges crypto 'bunker mode' over AI-broken ECDSA](https://postcutoff.com/e/2026-10-07-justin-drake-bunker-mode-ai-cryptography/index.md)
- People: [Pushmeet Kohli](https://postcutoff.com/person/pushmeet-kohli/), [Abhradeep Thakurta](https://postcutoff.com/person/abhradeep-thakurta/), [Dj Dvijotham](https://postcutoff.com/person/dj-dvijotham/), [Emmanuel Thomé](https://postcutoff.com/person/emmanuel-thome/), [Nadia Heninger](https://postcutoff.com/person/nadia-heninger/)
- Archived: 2 posts, listed in https://postcutoff.com/e/2026-11-06-deepmind-ai-agents-rsa-1024-cryptanalysis/index.json