Interestingly it is Microsoft who filed a patent for DRM-style locking of AI models to verified devices (published July 2026): https://patentlyze.com/patent/microsoft-drm-ai-models-explai...

So they can avoid the embarrassment when Copilot migrates to Qwen 4

AI is actually the perfect use case for homomorphic encryption.

I wonder if this space is explored fully enough at the moment.

Aside from some implementation details, it's conceptually much easier than doing it for a SQL database.

That's older than current AI/LLM/NVIDIA wave. Many application specific DSPs probably carry their model weights in an encrypted manner. If not, we would have seen the extremely performant face recognition and tracking models extracted from professional cameras already.