Four years ago, about a dozen credit cards equipped with chip-and-PIN technology were stolen in France. In May 2011, a banking group noticed that those stolen cards were being used in Belgium, something that should have been impossible without the card holders inputting their PINs. That’s when the police got involved.
The police scanned the international mobile subscriber identity (IMSI) numbers present at the locations where the cards were used and at the times they were used, and then they correlated those IMSI numbers to SIM cards.