As I was reading US patent 8289130 ‘Systems and methods for identifying unauthorized users of an electronic device’, I was just asking myself questions on how come this is patentable? How does it meet the three main criteria to be patentable?
The three criteria for patentability in the US, as you probably know, are novelty, usefulness and non-obviousness. Let's look at the first claim:
Basically, it says if memory usage of a device suddenly shoots up, the current user is unauthorized. It's obviously some sort of a heuristic method. Let's evaluate this claim for each of the three criteria.
Novelty: Since the examiner apparently could not find any prior art reference that describes everything the claim requires, it meets the novelty criteria. Of course, this may change if a reference is found that does describe the method but was not found by the examiner. Without knowing better, we have to trust the examiner's search results. (You can actually go into USPTO PAIR and inspect the examiners search methodology and results, if you so desire.)
Usefulness: The patent describes a method for detecting unauthorized usage, such as when a device is stolen, so that it could potentially trigger some action (such as sending an alert.) I think most would agree that that is useful, in both the ordinary and patent law sense.
Non-obviousness: This is the trickiest part of evaluating a claim. From an examiner's perspective, a claim is probably obvious if two or more (usually up to 3 - 4) relevant prior art references can be combined to cover all elements of a claim. This is not a hard-and-fast rule, but it's needed because examiners need some publicly available historical record to support their judgement, otherwise the system would become too arbitrary and subjective. In this case, it seems the examiner could not find any (or enough) such prior art references to invalidate the claim.
However, even from a layman's perspective, I personally don't find the claim obvious, in the plain meaning of the word; I just don't get how increased memory usage is indicative of unauthorized use. I'll have to trust the patent when it asserts that sudden increase in memory usage probably means the device is being "jailbroken." But then again, I'm not knowledgeable about the field of locking down devices or hacking them, where it may even be a commonly known effect.