Payphone service for third generation mobile systems

The pre-payment application for third generation mobile systems is intended to increase service usage by introducing new means of payment such as the pre-payment. This application takes into account the mobile environment specificities (fragility of the air interface from the security point of view, roaming, mobility functions and specific rules for charging). Firstly, the paper analyses the threats. It then proposes features to provide a high level of security and describes the procedures to guarantee that. To manage payphone keys in multi-operator environments, several scenarios are treated. The last part of the paper describes an implementation of the pre-payment application in an IN architectural context