While inside DeTeMobil, SKiMo also learned how to interpret some of the mapping and signal-strength data. The result? If one of the company's customers has his mobile turned on, SKiMo says he can pinpoint the customer's geographic location to within one kilometre. The customer doesn't even have to be talking on the mobile. All he has to do is have the phone turned on, waiting to receive calls.
SKiMo tracked one customer for an afternoon, as the man travelled across Germany, then called the customer up. It turned out they spoke the same European language.
`Why are you driving from Hamburg to Bremen with your phone on stand-by mode?' SKiMo asked.
The customer freaked out. How did this stranger at the end of the phone know where he had been travelling?
SKiMo said he was from Greenpeace. `Don't drive around so much. It creates pollution,' he told the bewildered mobile customer. Then he told the customer about the importance of conserving energy and how prolonged used of mobile phones affected certain parts of one's brain.
Originally, SKiMo broke into the mobile phone carriers' network because he wanted `to go completely cellular'—a transition which he hoped would make him both mobile and much harder to trace. Being able to eavesdrop on other people's calls— including those of the police—was going to be a bonus.
However, as he pursued this project, he discovered that the code from a mobile phone manufacturer which he needed to study was `a multi-lingual project'. `I don't know whether you have ever seen a multi-lingual project,' SKiMo says, `where nobody defines a common language that all programmers must use for their comments and function names? They look horrible. They are no fun to read.' Part of this one was in Finnish.
SKiMo says he has hacked a number of major vendors and, in several cases, has had access to their products' source codes.
Has he had the access to install backdoors in primary source code for major vendors? Yes. Has he done it? He says no. On other hand, I asked him who he would tell if he did do it. `No-one,' he said, `because there is more risk if two people know than if one does.'
SKiMo is mostly a loner these days. He shares a limited amount of information about hacking exploits with two people, but the conversations are usually carefully worded or vague. He substitutes a different vendor's names for the real one, or he discusses technical computer security issues in an in-depth but theoretical manner, so he doesn't have to name any particular system.