Yesterday, Ars reported that several cell phone manufacturers have made the rather unremarkable claim that when a phone is turned off, it is off. Some of them did speculate about the possibility of some intriguing malware that causes your phone to look off even when it’s not. This was only an issue because somebody told the Washington Post that the NSA could track a phone even when it’s off.

Technically, I think it would be more accurate to say that somebody told somebody who told somebody who told the Post, just like in the aptly named game of telephone. If we replace the words turned off with not in use, the claim becomes a lot more plausible and a lot less interesting. Is it reasonable to believe somebody used off as a synonym for not in use?

If someone were to come to my house and I asked them if the iPad sitting on my coffe table was on or off, what would they answer? The screen is dark and it’s not making noise, so it’s off, right? Maybe it’s idle or sleeping or suspended, but I’ve noticed people not concerned with technical minutiae don’t always make such a distinction. When I go to the (live) theater, there’s always an announcement requesting patrons turn off their cell phones. “Not just off, but completely powered down.” That’s an unusually precise, not to mention redundant, way to phrase the request. Unless, of course, the theater has had some experience with different interpretations of what it means for a cell phone to be turned off.

Is there any evidence to support this interpretation? Go read the Post article. On page two, it begins a story about a SEAL asking to track a phone. The NSA operator was reluctant because they didn’t have authorization. But it makes very clear that the analyst usually dealt with conversations (when a phone is definitely on) and implied that the phone was in use at the time of the request. Then we move onto “The Find” about tracking phones that are off. Or perhaps just not in use? My reading suggests that in 2003 they were only monitoring phones in active use, but in 2004 they were hooked in to all of the cell tower triangulation data.

I am reminded of my favorite magic cell phone story. As reported by cnet, the FBI can remotely activate a phone’s microphone even when turned off. I’ve always been rather skeptical of this story. The evidence comes from a court filing, but it’s a short statement even shorter on details. Several other interpretations are possible, even assuming the statement is literally true. Also note that the person writing the opinion (the judge) is not the same person who is using the bug. It’s not like the FBI was asked to demonstrate this mysterious remote activation technique in the courtroom. We just have to trust them when they say they have it.

But should we? Now that we know about parallel construction and all manner of other government hijinks, why would anyone believe anything in a government report? Here’s another scenario. The NSA feeds some info to the FBI, who now have to explain where it came from. “That must have been something we overheard with our wiretap.” Somebody points out that the target’s phone was turned off at the time. “Oh, uh, it must have been our special remotely activated wiretap. Yeah, that was it.”

In conclusion, there’s a danger when dealing with phrases like turned off. They don’t sound ambiguous. Alice could tell Bob it’s turned off, and both of them would have complete confidence they knew exactly what the other meant even while they actually have rather different interpretations. The problem is amplified when a seemingly unambiguous phrase is replaced with one that is truly unambiguous. Alice tells Bob “it’s not in use”. Bob tells Carol “it’s off”. Carol tells Dave “it’s powered down”.