Rec. ITU-T H.233 (03/1993) – CONFIDENTIALITY SYSTEM FOR AUDIOVISUAL SERVICES
FOREWORD
CONTENTS
1 Introduction
2 Properties of the system specified
    2.1 Confidentiality
    2.2 Algorithm specification
3 The confidentiality mechanism
    3.1 Description of operation
        3.1.1 Controls and indication within the H.221 frame
        3.1.2 Message formats
        3.1.3 Unenciphered ECS channel
    3.2 Transmission encryption method
    3.3 Procedure for use of the system
4 Multilayer protocol encryption
Appendix I – Encryption and decryption for 2 x B channels
Appendix II – Encryption algorithms and their parameters
References