The goal of the Non-repudiation service is to generate, collect, maintain, make available and validate evidence concerning a claimed event or action in order to resolve disputes about the occurrence or non occurrence of the event or action. This part of ISO/IEC 13888 specifies mechanisms for the provision of some specific, communication related non-repudiation services using asymmetric techniques.

Non-repudiation mechanisms are specified to establish the following non-repudiation services:

• non-repudiation of origin,
• non-repudiation of delivery,
• non-repudiation of submission,
• non-repudiation of transport.

Non-repudiation mechanisms involve the exchange of non-repudiation tokens specific for each non-repudiation service. Non-repudiation tokens consist of digital signatures and additional data. Non-repudiation tokens shall be stored as non-repudiation information that may be used subsequently in case of disputes.

Depending on the non-repudiation policy in effect for a specific application, and the legal environment within which the application operates, additional information may be required to complete the non-repudiation information, e.g.,

• evidence including a trusted time stamp provided by a Time Stamping Authority,
• evidence provided by a notary which provides assurance about the action or event performed by one or more entities.

Non-repudiation can only be provided within the context of a clearly defined security policy for a particular application and its legal environment. Non-repudiation policies are described in the multipart Standard of Security Frameworks for open systems - Part 4: Non-repudiation Framework, ISO/IEC 10181-4.