CSA Preface 

Standards development within the Information Technology sector is harmonized with international standards development. Through the CSA Technical Committee on Information Technology (TCIT), Canadians serve as the SCC Mirror Committee (SMC) on ISO/IEC Joint Technical Committee 1 on Information Technology (ISO/IEC JTC1) for the Standards Council of Canada (SCC), the ISO member body for Canada and sponsor of the Canadian National Committee of the IEC. Also, as a member of the International Telecommunication Union (ITU), Canada participates in the International Telegraph and Telephone Consultative Committee (ITU-T). This Standard supersedes CSA ISO/IEC 11770-5:20 (adopted ISO/IEC 11770-5:2011). At the time of publication, ISO/IEC 11770-5:2020 is available from ISO and IEC in English only. CSA Group will publish the French version when it becomes available from ISO and IEC. 

This Standard has been formally approved, without modification, by the Technical Committee and has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group. 

Scope

 This document specifies mechanisms to establish shared symmetric keys between groups of entities. It defines: - symmetric key-based key establishment mechanisms for multiple entities with a key distribution centre (KDC); and - symmetric key establishment mechanisms based on a general tree-based logical key structure with both individual rekeying and batch rekeying. It also defines key establishment mechanisms based on a key chain with group forward secrecy, group backward secrecy or both group forward and backward secrecy. 

This document also describes the required content of messages which carry keying material or are necessary to set up the conditions under which the keying material can be established. This document does not specify information that has no relation with key establishment mechanisms, nor does it specify other messages such as error messages. The explicit format of messages is not within the scope of this document. This document does not specify the means to be used to establish the initial secret keys required to be shared between each entity and the KDC, nor key lifecycle management. This document also does not explicitly address the issue of interdomain key management.