Crypto U12 (part 2), crypto for mobile telecom

Crypto U12 (part 2), crypto for mobile telecom

1. GSM and UMTS key management

   • generation
     • user keys are generated by SIM manufacturer
     • user keys installed on SIM
   • establishment
     • established with user X when SIM is given to the user
     • user key is also given to carrier by the SIM manufacturer
   • storage
     • user key is stored on tamper resistant SIM
     • session keys (encryption and MAC) thrown away after each use
   • usage
     • user key only exposed briefly to encryt challenge response to base station

2. key hiearchy diagram

   • Crypto U12 GSM,UTMS Hierarchy Diagram