A system for providing secure services to a user via a communications network comprises an applications device including a data processor operable to provide a user service in accordance with an applications program requiring sensitive data. The system includes a smart card access device for accessing a smart card uniquely associated with the user, the smart card including an encryption key pre-stored in the smart card and a communications interface for communicating data securely via the communications network using the smart card encryption key. A trusted server is operable to communicate sensitive data to the smart card via the communications network by encrypting the sensitive data using the smart card encryption key. The sensitive data is decrypted and stored on the smart card. The applications program is operable to access the sensitive data on the smart card only following a successful mutual authentication between the smart card and the applications program. Secure communication of the sensitive data is thereby provided using an inherent security facility within smart cards such as Subscriber Identity Modules (SIM), which acts as a local server to the applications program.