ISO INTERNATIONAL STANDARD 9160 First edition 1988-02-01 INTERNATIONALORGANIZATIONFORSTANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEXKAYHAPOAHAAOPTAHM3ALMANOCTAHAAPTW3ALMM Information processing -- Data encipherment Physical layer interoperability requirements Traitement de I'information - Chiffrement de donnees -- Caracteristique interfonctionnement Reference number ISO 9160: 1988 (E) CopyightIntematinal Organization for Standardization Not for Resale Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee, International organizations, govern- mental and non-governmental, in liaison with IsO, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISo Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 9160 was prepared by Technical Committee ISO/TC 97, Informationprocessingsystems. Users should note that all International Standards undergo revision from time to time and that any reference made herein to any other International Standard implies its latest edition, unless otherwise stated. ? InternationalOrganizationforStandardization,1988 Printed in Switzerland yhmatinalgaizatiandardizai ed without license from IHS Not for Resale INTERNATIONALSTANDARD ISO9160:1988(E) Information processing - Data encipherment Physical layer interoperability requirements 0 Introduction International Standard apply to both synchronous and asynchronous operation in both full duplex and half duplex This International Standard specifies interoperability and modes. security related requirements for using encipherment at the The main body of this International Standard specifies physical layer of the ISO Open Systems Interconnection requirements which are applicable to the use of various (Osl) Reference Model in telecommunication systems encipherment algorithms. AnnexB specifies additional conveying Automatic Data Processing (ADP) information. requirements for the use of DEA (ANSI X3.92- 1981). This International Standard will facilitate the interoperation This International Standard also specifies two alternative of data encipherment equipment used in data communi- modes of synchronous operation cation facilities and systems that require cryptographic thedelayedoptionand the immediate option - which are mutually incompatible. protection. This International Standard also specifies two alternative The objectives of physical layer encipherment are to protect actions for BREAK signalling for asynchronous operation - against all forms of passive attack including traffic analysis. ClassAandClassB-whicharemutuailyincompatible insynchronous operation where all bits canbe enciphered whereas in asynchronous operation the start and stop bits 2 References can never be enciphered.This International Standard does notprovide for protection physical connection The following documents are referenced in this Inter- establishment. national Standard: This International Standard contains two annexes, A and B ISO 2382-9, Data Processing - Vocabulary - Part 9: Annex A is not an integral part of this International Data Communication. Standard. Annex B is an integral part of this International IsO 7498, Information processing systems - Open Standard. Systems Interconnection - Basic Reference Model. IsO 7498-2,Information processing systems - Open 1 Scope and field of application Systems Interconnection - Basic Reference Model. Part 2: Security Architecture!) This International Standardappli