scope:

A privacy system consists of two parts, the confidentiality mechanism or encryption process for the data, and a key management subsystem. This European Telecommunication Standard (ETS) is based on ITU-T Recommendation H.233 [1] and describes the confidentiality part of a privacy system suitable for use in narrowband audio-visual services conforming to ITU-T Recommendations H.221 [2], H.230 [3], H.234 [4], and H.242 [5]. Although an encryption algorithm is required for such a privacy system, the specification of such an algorithm is not included in this ETS. The system caters for more than one specific algorithm.