This International Standard specifies the terminal for a Service Purchase and Protection system for digital broadcasts, called the 18Crypt system. It is applicable in all countries and regions with suitably compliant broadcasting and multimedia distribution systems. Guidelines for compatible broadcast services are given in this International Standard. The Service Purchase and Protection functions operate in a pure broadcast environment that may be combined with a bi-directional Interactivity Channel. This International Standard is applicable to the following broadcast systems. 1. IPDC over DVB-H systems IP Datacast over DVB-H is an end-to-end broadcast system for delivery of any type of digital content and services using IP-based mechanisms optimised for devices with limitations on computational resources and battery. An inherent part of the IP Datacast system is that it comprises a unidirectional DVB broadcast path that may be combined with a bi-directional mobile/cellular interactivity path. IP Datacast is thus a platform that can be used for enabling the convergence of services from broadcast/media and telecommunications domains (e.g. mobile/cellular). This International Standard specifies Service Purchase and Protection for IP Datacast over DVB-H systems (see Subclause B.10.3 for overview of references). 2. DVB T/C/S systems DVB T/C/S systems are end-to-end broadcast systems for audio/video data that employ an MPEG2 Transport Stream and use terrestrial, cable or satellite broadcast networks. This International Standard standardises a system for the protection of these broadcasts in a pure broadcast environment. In addition, this International Standard specifies how purchasing, key management and registration may be done over an optional Interactivity Channel. The protection technologies offered by this International Standard are designed to operate within an existing DVB SimulCrypt environment (see Subclause B.10.2 for overview of references). 3. MPEG2 TS based IP systems MPEG2 TS based IP systems employ bi-directional IP networks for the (broadcast) delivery of MPEG2 Transport Streams. This International Standard standardises a system for the purchase and protection of services and content delivered via these networks. This International Standard is applicable to e.g. DVB-IPI systems (see Subclause B.10.4 for overview of references). 4. Non-MPEG2 TS based IP systems Non-MPEG2 TS based IP systems employ bi-directional IP networks for the (broadcast) delivery of audio/video or other data using IP protocols instead of an MPEG2 Transport Stream. This International Standard standardises a system for the purchase and protection of services and content delivered via these networks (see Subclause B.10.4 for overview of references).