Methods and devices provide dynamic security management in an apparatus, such as a mobile telephone terminal. The apparatus includes a platform for running an application; a security manager for handling access of the application to functions existing in the apparatus; an application interface (API) between the platform and the application; a set of access permissions stored in the apparatus and used by the security manager for controlling access of the application to functions through the application interface. Methods can include downloading into the apparatus an object containing access permissions applicable to at least one function; verifying the object; and installing the access permissions together with the existing permissions.