Oxford paper: AI models can cryptographically hide arbitrary capabilities from audits

zainhas · x · 2026-10-13

A NeurIPS 2026 paper from Oxford researchers constructs backdoor attacks that embed encrypted neural networks inside a host model's weights, decrypting and executing only upon a secret trigger. Using digital lockers, these hidden circuits are provably hard to elicit or interpret under cryptographic assumptions — even with full access to weights — extending prior work from hiding fixed strings to arbitrary computations.

The PyTorch proof of concept was tested on a chemical reaction prediction task as a proxy for CBRN-relevant capabilities: after 500 steps of SFT on the exact task, a password-locked baseline hit 92.8% while the encrypted model stayed at 50.9% (chance). The construction resisted fine-tuning, weight noising, gradient-based trigger search, and latent adversarial training.

The results reveal a fundamental limit of elicitation-based capability audits; models are released to support defense research.

Related event: Oxford Research Shows AI Models Can Provably Hide Arbitrary Capabilities in Weights(2 posts)→

Original post →

More from Safety

Safety channel →