Gemalto's findings of its investigations into the alleged hacking of SIM cards
Can anyone elaborate on why it's supposedly only a problem for 2G?  "If someone intercepted the encryption keys used in 3G or 4G SIMs they would not be able to connect to the networks and consequently would be unable to spy on communications."  Why not?  I feel like there is a "merely" missing from this sentence -- if so, what more than keys do they need to spy?Are they basing this on the specific type of key discussed in the documents?  I don't know a lot about it, but I'm inclined to believe there are valuable keys burned-in to 3G+ cards too.I also wonder if there is a downgrade attack to force 2G, so that those keys are not completely worthless.