"William H. Geiger III" <whgiii@amaranth.com> writes: |It's an intresting side note that the reason why the Cell Phones in this |country do not use strong crypto is because of the intervention of the FCC |and associated Federal LEA's. Not that it would have mattered except to scanner owners with too much time on their hands. The LEAs can intercept at the cellular base station where the air segment traffic is decrypted. This is true for GSM, TDMA, and CDMA. True security requires end-to-end encryption. While slightly possible for mobile-to-mobile calls where each phone has the encryption engine, it all breaks down if the base station doesn't preserve a digital pathway all the way through. Most base stations do tandem vocoding for mobile-to-mobile connections as it's the easiest engineering solution. For mobile-to-landline, the landline options are decidely minimal. If you go with STU-III you have the problem of a fixed-rate 4800 baud modulation sucking up bandwidth. That could be put in the base station but then the path is no longer end-to-end. /pbp