running voice data/encryption on compal?

Harald Welte laforge at
Fri Jan 14 20:29:28 UTC 2011


the usual problems with end-to-end encryption in GSM come into play:
* as the voice path is not transparent but transcoded any number of times
  in the core network, you cannot simply encrypt the codec frames but gqwill
  have to initiate a CSD ('modem') connection.
* not many networks support it anymore
* calling rates are more expensive
* you immediately leave a visible trail, since nobody else uses CSD

And no, neither is the ARM7 fast enough for any crypto, nor do we implement
CSD at all.

- Harald Welte <laforge at> 
"Privacy in residential applications is a desirable marketing option."
                                                  (ETSI EN 300 175-7 Ch. A6)

More information about the baseband-devel mailing list