Although Roam Mobility doesn’t say this explicitly on its homepage, Aboulhosn pointed out that as a “disposable” service, Ready SIM makes it much more difficult for a user to be surveilled or tracked.
Firstly, he said, the company uses a proxy service, its own private APN separate from T-Mobile. ”So even if you look at the traffic on the Web, it looks like it’s all going to the same place: the proxy server.”
When I ran that by Christopher Soghoian, the principal technologist at the American Civil Liberties Union, he offered up this observation by e-mail:
Anonymous SIMs tend to not be terribly anonymous, unless you use them with a brand new phone.
There is a unique serial # associated with the SIM (IMSI), and another unique serial associated with the phone (IMEI). You can pop in a new SIM card every day or two, but the serial for your phone will stay the same. Switching SIM cards with the same phone is a behavior that sticks out like a sore thumb when folks analyze carrier logs. I’ve even seen surveillance vendor marketing materials that claim to be able to recognize this behavior.
Getting a new cell phone every few days gets expensive, fast.
Oh, and on top of that, you can’t use it at your house, office, or anywhere else associated with your actual identity or the location data gives it away.
Staying anonymous with a cellphone is damn difficult.
When I ran Soghoian’s comments back to Roam, Troy Kleweno, the company’s chief technology officer, responded this way:
Yes, we aren’t breaking any laws and devices all have an IMEI. But in order for anyone to pull records and see the IMEI they first have to pin a person to a phone number. In order to do that, one of two things needs to happen:
1) The user has registered the device at activation or some other time (we don’t even know who our users are)
2) You can prove that a MSISDN [another important number, uniquely identifying a subscription in a GSM or a UMTS mobile network] or IMEI belongs to a user.
a. For IMEI this is difficult because no one knows it until they see the records, which they can’t see until they know who owns the IMEI.
b. For MSISDN, the temporary nature of the device makes it very difficult to ascertain who owns the MSISDN.
So this is not guaranteed protection for life by any means, as that would certainly be illegal anyway. But it does offer a layer of separation for sure. If someone uses this program repeatedly with the same device, after a while one of their phone numbers will be detected and a subpoena request will yield those CDRs.
At that time, the IMEI can be gleaned and then a subsequent subpoena could pull records for that IMEI.
IMEI is mainly used for stolen phones (reported as such) and for fraud detection (spamming, SIM boxes etc.). Roam certainly wants to keep those guys off our network as well because it gets very expensive.
Kleweno added later, “While the carrier assigns an IP to the device, the proxy assigns an additional one which goes out to the Internet. So there is an IP switch mid-stream. The Call Detail Record (CDR) that Roam receives does NOT contain the actual IP address of any visited site. So here again, the theme is ‘not untraceable, just shielded—and completely legal.’”