And at the latest CCC congress<\/a> in Berlin, Karsten Nohl and Henryk Pl\u00c3\u0192\u00c2\u00b6tz gave a brilliant and inspiring presentation about their findings (google video<\/a> or MP4<\/a>).<\/p>\n The researchers used a ‘simple’ setup. With lots of patience, they managed to slice off the top of the chip and reach the first layer. Using a 500X magnifying microscope they took a high resolution picture of this layer. They then used some very fine polish and ‘really really carefully’ polished away the first layer, making the second layer visible. And took another picture. And so on. The story does not say in how many tries they succeeded to make five high quality images, but it must have been a hell of a job. Not to mention laying these images on top of each other and trying to make sense out of it. According to the researchers this all was ‘painful work’. Well, I take my hat off for them as it the kind of research I greatly admire!<\/p>\n It took them some time, but they managed to reverse engineer the mifare<\/a> encryption algorithm this way. And by that the Mifare system seems history (for serious applications).<\/p>\n Mifare heavily relies on keeping the encryption scheme secret. The problem is cheap\/affordable RF-ID chips do not have enough CPU to do serious crypto, so keeping the inner working secret is the only defense. And during the research many more weaknesses in the Mifare system were found. Even if you do not understand everything, I strongly encourage everyone to view the video<\/a> of the presentation. It is inspiring to say the least, and shows with determination even the most complex problem can be tackled (well …. almost). <\/p>\n The real lesson learned is that security through obscurity does not work, and only buys you some time. But it will bite you in the long run when using it in widely deployed systems. The problem now is millions of Mifare chips are deployed in the field in a huge install base. And most of the users are completely unaware of the disaster that is coming …<\/p>\n So far the users are ‘safe’. The researchers have not given out the full details on Mifare…. yet. But please take their advice serious: “If you rely on Mifare<\/a> for anything, start migrating!”. More information about the mifare hack can be expected in the very near future.<\/p>\n![\"Click](\"http:\/\/blackbag.toool.nl\/images\/mifare.jpg\")
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\n* Karsten Nohl pointing out the different layers<\/p>\n