| 摘要 |
A fraudulent intruder can eavesdrop on a call by removing information about an encryption algorithm when a multimode mobile station sends an unpro-tected initial signaling message containing this information over the radio interface to the mobile telecommunications system. The attempt can be pre-vented in a universal mobile telecommunications system (UMTS) comprising at least two radio access networks providing mobile stations with access to at least one core network, a multimode mobile station, and at least one core network. During connection setup with a first radio access network, the mul-timode mobile station sends an unprotected initial signaling message that includes information about those encryption algorithms that the multimode mobile station supports when it communicates in a second radio access network. The first radio access network saves some or all the information of it. Then it composes and sends an integrity-protected message that includes information about the encryption algorithms supported by the multimode mobile station in the second radio access network.
|
