That you’re phrasing it as “training an LLM to keep secrets” suggests a misapprehension: A downloadable LLM that knows secrets fundamentally cannot be expected to keep them. The fixable condition is much weaker: capabilities, if an LLM has the capability to do dangerous things.

The problem for secrets in general (which is a separate issue to LLMs, I interpreted you asking me about the EU Chat debate as an attempted gotcha not as a directly connected item) that no matter what you do, we’re unstable: not having secrets breaks all crypto which breaks all finance and approximately all of the internet, while having it creates a safe (cyber)space for conspiracies to develop without detection until too late. And also no room for conspiracies means no room to overthrow dictatorships, so if you get one you’re stuck. But surveillance can always beat cryptography so even having the benefits of crypto is an unstable state.

See also: Gordian Knot.

Find someone called 𐀀𐀩𐀏𐀭𐀅𐀨 to solve the paradox, I hear they’re great.