Temporary mobile user certificate for mobile information services in UMTS

This paper presents an efficient public-key protocol for mutual authenticat ion and key exchange designed for mobile information services in UMTS. Cert ain modifications to the ASPeCT registration protocol is proposed to introd uce Temporary Mobile User Certificate in UMTS environments. Proposed 'Tempo rary Mobile User Certificate. digitally-signed by the private signing key o f the TTP located in the user's visiting domain, will be issued to the user during the registration protocol. ASPeCT AIP protocol can be modified to r educe communication overhead and speed up verification process using Tempor ary Mobile User Certificate between the user and the Value-Added Service Pr ovider (VASP) located in the user's visiting domain. Furthermore, Temporary Mobile User Certificate can provide anonymity for a mobile user during the ASPeCT AlP protocol.