Karsten works with Chris Paget at H4RDW4RE, a consulting firm they started to focus on hardware security. While all the high-end pentest firms will do hardware, only a couple have a practice focus in hardware; they compete with Nate Lawson's Root Labs and after that there's pretty much just Paul Kocher's Cryptography Research. These guys are going to have a blast.

A direct link to the presentation:

http://www.scribd.com/doc/18668509/HAR2009-Cracking-A5-GSM-E...

The long and the short of it, they're going to take the academic result that you can precompute A5 and use a GPU cluster to build a rainbow table cracking implementation.

This result is a couple steps away from apocolyptic, but not all the way there:

* They haven't subverted GSM base stations (this is going to turn out to be doable, though). They can't pick a phone at random.

* They aren't publishing the GNU Radio code to sniff GSM. There are several free GSM projects, but putting the pieces together still requires talent, unlike wifi cracking.

* Regardless of whether these attacks are ever used in the wild, this will probably have a big effect on financial security, where GSM is used as a safe out-of-band authentication mechanism.