For voice calls, it is not possible to merely insert a more secure crypto function (e.g., IDEA) inside the less secure A5 crypto, unless the GSM base station's protocol is aware the subscriber unit is using the more secure crypto. Otherwise, when the GSM base station unwraps the A5 encrypted data stream, which it assumes will contain digitized voice packets in the clear, it will not find what its looking for and will be unable to convert the packets to a circuit-switched voice signal. If, as I have previously stated, the subscriber instead uses the data port of his instrument and establishes a data link with his payload protected by the more the secure crypto this is entirely feasible. -- Steve PGP Fingerprint: FE 90 1A 95 9D EA 8D 61 81 2E CC A9 A4 4A FB A9 --------------------------------------------------------------------- Steve Schear (N7ZEZ) | Internet: azur@netcom.com Lamarr Labs | Voice: 1-702-658-2654 7075 West Gowan Road | Fax: 1-702-658-2673 Suite 2148 | Las Vegas, NV 89129 | --------------------------------------------------------------------- Internet, electronic currency and wireless development 1935 will go down in history! For the first time a civilized nation has full gun registration! Our streets will be safer, our police more efficient, and the world will follow our lead in the future! --Adolf Hitler