We were talking at Gong Bao Thursday a few weeks ago about the announcement from Crime Stoppers that they now accept reports by SMS. What we found intriguing is that they claim that the text messages are “anonymous,” which is a curious claim because although it’s possible to make an “anonymous” call from, say, a pay telephone, when you send an SMS from your mobile, your number is sent too, as the “from” address.
If you read the TipSoft SMS Security and Anonymity Overview — they’re the company that runs this system — you’ll see that, in fact, your anonymity is simply a policy, not a technical fact. The most important sentence in the document is this one:
SMS messages from mobile phones are sent to a secure server located in Canada that is independently operated by Mr. Jacksch’s company, where the mobile phone number is encrypted and assigned an alias.
So, in other words, they’re using a third-party to make Crime Stoppers blind to the calling number, but the calling number is still being sent as part of the SMS, and from a technical perspective the calling number is available to the service, even if it is later encrypted. This seems like a pretty liberal interpretation of the concept of anonymity, especially because we’re being asked to trust an unnamed third party to protect our privacy. I’m not sure, if I was going to turn in my local mob boss, I’d be comfortable with this.
Later our discussion wandered from snitch-by-SMS to the mechanics of regular old low-tech snitching, and somebody made a joke about how they would have to pay you by doing something cloak and dagger like leaving an envelope under a tree. It turns out that this is pretty much how it does work.