Comment by maxbond
7 hours ago
> ALL context/prompt is instructions, there is no data. It is just unsolvable, period.
That really isn't true. There's no law of physics preventing you from having separate data and instruction inputs to models. The model's transcript format generally distinguishes between prompts and instructions and tool output and such. This isn't a solved problem, and it's possible it's entire unsolvable, but it probably is possible (in general, not with current models) to reject prompt injection to several nines.
This is a lot like making the same statement about CPUs, "the von Neumann architecture doesn't distinguish between code and data so it's impossible to reject malicious instructions." There's actually a lot you can do to reject malicious instructions, you can prevent execution in certain pages, you can prevent certain privileged instructions from being executed in certain pages, you can employ stack cookies, et cetera. Do they prevent all exploitation in all circumstances? No. But each component does function in it's lane and it is possible to create programs with high (though not absolute) guarantees against unauthorized code execution by composing them.
Similarly, you could prevent certain tokens from appearing in the prompt portions of a transcript, you can have a model with multiple input heads only one of which is trusted, etc. I'm not saying those techniques will necessarily work, but it is more complex than "models can only possibly take a single and undifferentiated input stream".
A lot of the solutions in the CPU space involve things like memory allocation flags, NX bits, canaries, etc. that fire deterministically. Those things are fundamentally not applicable to LLMs, and without those things modern software would be in a vastly worse place.
You could imagine that there are things to change around LLM architecture that will improve its ability to reject prompt "injection", but I think it's fundamentally true that from an information theory perspective there's no bright line between "instruction" and "input data" possible.
Nondeterminism is a red herring. There is a bright line between instructions and data right now, in virtually every transcript format. That we have not succeeded in training an LLM to respect it to a very high degree doesn't imply it is impossible; that they are nondeterministic doesn't imply it is impossible; only that we won't succeed 100% of the time.
A cosmic ray (or rowhammer attack) could flip an X bit too, there isn't anything truly deterministic under the sun.