CONTENTS

 1     Scope
 2     Normative references
 3     Abbreviations
 4     Properties of the system specified
        4.1     Confidentiality
        4.2     Algorithm specification
 5     The confidentiality mechanism
        5.1     Description of operation
                  5.1.1     Controls and indication within the H.221 frame
                  5.1.2     Message formats
                  5.1.3     Unenciphered ECS channel
        5.2     Transmission encryption method
        5.3    Procedure for use of the system
 6     Encryption of MLP channel
Annex A – Encryption algorithms and their parameters
        A.1     Scope
        A.2     Normative References
        A.3     FEAL
        A.4     DES
        A.5     IDEA
        A.6     TDEA
        A.7     AES
Appendix I – Encryption and decryption for 2 × B channels
Appendix II – Audiovisual privacy communication procedure