(aside: fascinating example of a US military slide deck, like a 90s fever dream made in Harvard Graphics)
Here’s also a Voices from DARPA episode, which suggests they’ve been funding research since at least 2012: https://blubrry.com/voices_from_darpa/30975140/episode-17-gu...
In terms of ensuring designs are not tampered with seems like watermarking is the direction they’re exploring.
Another fascinating concept was the “silicon odometer” to ensure recycled chips aren’t reintroduced into the supply chain.
Asianometry has a fascinating video on that issue: https://youtu.be/7epnv43jGV8