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 Canadian Advisory Committee (CAC) 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 CAN/CSA-ISO/IEC 9798-5-05 (adoption of ISO/IEC 9798-5:2004, second edition, 2004-12-01). At the time of publication, ISO/IEC 9798-5:2009 is available from ISO and IEC in English only. CSA 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 approved as a National Standard of Canada by the Standards Council of Canada. Scope This part of ISO/IEC 9798 specifies entity authentication mechanisms using zero-knowledge techniques: - mechanisms based on identities and providing unilateral authentication; - mechanisms based on integer factorization and providing unilateral authentication; - mechanisms based on discrete logarithms with respect to numbers that are either prime or composite, and providing unilateral authentication; - mechanisms based on asymmetric encryption systems and providing either unilateral authentication, or mutual authentication; - mechanisms based on discrete logarithms on elliptic curves and providing unilateral authentication. These mechanisms are constructed using the principles of zero-knowledge techniques, but they are not necessarily zero-knowledge according to the strict definition for every choice of parameters.