Editing P2p mobile carriers (section)

=== 10.2.1. … Ideally full knowledge of authentication routines ===

For authentication with the MsC, the GSMA have specified many authentication procedures and key derivation functions that can be used depending on the network (2G, 3G, and so on.)

Unfortunately, while ciphering functions have been standardised [ciphering], the functions to use for authentication '''are only a suggestion''' [closed-auth][carrier-milenage][op-specific]. The mobile system is flexible enough to allow each operator to use a different set of algorithms, and some of the standard functions allow an operator to “customise” the algorithm with an operator-specific key (you can think of this like a salt) [op-key].

If every operator were to use a proprietary group of authentication algorithms its not going to be practical to study them. To be determined. The bigger problem is operator-specific keys. How hard are they to extract from a SIM? It might be practical to reverse a few operator keys from the most popular carriers if they only change every few months, but not on a per-SIM basis. And that’s assuming that the chips can be reversed.

Numerous attacks have been found in UUIC U/SIM cards [java-card-attacks], but this is a very specialised area of research [java-card-reverse][oscilloscope].

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