The present invention relates to an interface module for a host (2) such as a digital television decoder, permitting the processing of information coming from the host (2) in a conditioned manner subject to a conditional access system (11), comprising authorization means (7) by which the user justifies his access rights.The module has at least one means (8) for identifying the authorization means (7); means (10) for storing a plurality of conditional access systems (11), processing means (9) adapted to process the information coming from the host (2) utilizing the conditional access system (11) corresponding to the authorization means (7) identified by the identification means (8), permitting to exploit a plurality of conditional access systems (11) within the same module The invention also relates to a decoder and a method adapted to be performed by the interface moduleFor use in digital television decoders