This document defines the TPEG conditional access information (CAI) application. It allows the protection of the content of a TPEG service from unauthorized access. It further supports the management of subscriber information (e.g. control words and entitlement control message, ECM) on client devices in order to setup, prolong or revoke a subscription on a given client device.The CAI application defines:— the logical channel for the transmission of the additional CAI, and— how the CAI is linked and synchronized to the scrambled content.This document is related to conditional access applied on the service component level. It can be integrated into different conditional access systems.NOTE The basic concept behind the CAI application is to transport CAI in separate TPEG service components of a dedicated application type and to define a service and network information (SNI) table that contains the link between scrambled content and related CAI.