Abstract: The invention relates to methods for storing and accessing user data (48) and configuration data (62) in a mobile device (10) that is connected to a user module (12). According to a first aspect of the invention, the user data (48) is stored in the mobile device (10) at least partially in encrypted form, and is decrypted, in access operations, using a decrypting function (66) of the user module (12). According to a second aspect of the invention, the configuration data (62) is stored in the user module (12). The configuration data (62) indicates whether, or to what extent, an application program (46) is allowed to be executed by the mobile device (10). Security and protection against unauthorised access to user data (48) and application programs (46) in the mobile device (10) are increased by the invention.