I've heard this is the general case, but is it proven that a prompt can always be recovered? I'm thinking particularly of cases where the LLM supports very larg

I've heard this is the general case, but is it proven that a prompt can always be recovered? I'm thinking particularly of cases where the LLM supports very large prompts, on the order of millions of tokens. It would be interesting to see if there is a way to bake in the prompt with the weights which may also be a valuable performance improvement, in addition to obscuring the prompt.