Without using them, one iPhone or laptop is indistinguishable from another of the same model — to the human eye, at least. A team of researchers, though, has developed a tool that can tell gadgets apart based just on the electromagnetic noise they create. Developed by Disney Research, the new technique — called EM-ID — analyses the electromagnetic signals emitted by electronic devices and attempts to use them to differentiate between gadgets of the same make and model. Disney Research's Chouchang Yang explains how that's possible in a press release:
Electromagnetic emissions are highly structured and a direct manifestation of the circuits that generate them. But variations in the manufacturing of all components and in final assembly create differences in the EM signal that enable us to differentiate, for example, a laptop computer from another laptop of the same make and model.
The system uses a simple software-defined radio as a reader, which feeds the signal into software for processing. Then, it identifies the relative strength of 1000 different frequency components to create a digital fingerprint for the device, which can be used to tell it apart from others. The team presented the work at an IEEE conference this week.
It's not always perfect, but it can successfully identify individual devices with 95 per cent accuracy. The accuracy varies depending on device: Cheap toy lightsabers can be uniquely identified from each other 100 per cent of the time, whereas the figure drops to 72 per cent for an iPhone 6. That difference is likely down to the fact that expensive devices undergo more painstakingly consistent production processes, with variations between components kept to a minimum.
In their research paper, the team writes that "EM-ID provides a zero cost method of uniquely identifying, potentially billions of electronic devices using their unique electromagnetic emissions." Privacy advocates, please form a line.
Image: Disney Research