A blacklist file was found by an iPhone hacker and the internet is all abuzz over the possibility that Apple has a kill switch for applications. Well of course they do- Apple clearly shows by their insistance on the App store that they will control what gets run on the device- but I don’t think the blacklist file mentioned is that mechanism. Showing up in the location cache is a really sketchy area to put a file that blacklists applications, unless it is an exceptionally stupid instance of security through obscurity, so I think people misunderstand what it is for.

Now if I were Apple and I wanted complete control over what ran on the device I would only allow the device to run signed applications so that both the identity of the app author can be checked and the integrity of the binary can be scrutinized. I would insist on being the only CA, which I could do because all apps have to go through my store *anyway*, so why not include issueing certificates in the whole deal. I would then publish a certificate revocation list via SMS at regular intervals so that the user has no control of when an app gets blacklisted and I can count on it being pushed to the device.

This isn’t a foolproof design but it does provide pretty decent control over the platform. In essence it isn’t really any different from what console manufacturers do. People seem willing to accept that they don’t actually have control over the device the bought, and have certainly been willing to deal with the draconian oversight of cell carriers for years, so they would very likely accept this from Apple. So what if they suddenly lost they ability to use an application that they ultimately purchased from Apple?

Is this what Apple is doing? I don’t know. But given their aims it seems the best way to do it. I hate touch screen interfaces no matter how slick they are done, so I won’t be investigating myself.

~ Joshbw