The present document specifies a Virtual Machine which is intended for inclusion in the implementation of digital television receivers and Set Top Boxes@ and which is able to provide a secured environment for executing Conditional Access kernel or Digital Rights Management client applications. The intention is to provide a uniform execution environment in which such clients can operate in the knowledge that minimum ECI Host performance requirements are met@ that a standard API is provided to be used for retrieval of essential security data from content (i.e. encapsulated with content) or via external networks (e.g. the Internet) and where resources can be accessed from the ECI Host environment in a standardized way. The presence and use of the VM allows to exchange CA/DRM clients at will and to support multiple simultaneous instances of such clients in ECI Hosts so that users and operators are not tied in to a particular content protection provider and that they can use security solutions of different types to suit differing content types. For ContentProtection system providers@ it ensures the availability of a known execution platform that does not require specific integration with any and every vendor of ECI Host devices.