Objective This document is the IPTV Interoperability Forum (IIF) Default Scrambling Algorithm (IDSA) Interoperability Specification that is designed to meet the following objectives: ? The specification focuses on IPTV interoperability issues only. ? The specification describes a default scrambling/de-scrambling algorithm. ? The specification describes the signaling for the selection and use of alternative scrambling algorithms. ? The specification describes a default scrambling/de-scrambling algorithm that can be efficiently implemented in both hardware and software. ? This specification only addresses scrambling of MPEG-2 Transport Streams. There are expected to be additional scrambling profiles for use with other transports of IPTV content as these are defined by the ATIS IIF. Specifications for any additional scrambling profiles will be given in future revisions of this document. The specification assumes that the Digital Rights Management (DRM) system is a black box.