This part of ISO/IEC 13888:2004 serves as a general model for subsequent parts specifying non-repudiation mechanisms using cryptographic techniques. The goal of the non-repudiation service is to generate, collect, maintain, make available and verify evidence concerning a claimed event or action in order to resolve disputes about the occurrence or non-occurrence of the event or action. There are two main types of evidence, the nature of which depends on cryptographic techniques employed: the secure envelopes generated by an evidence-generating authority using symmetric cryptographic techniques, and digital signatures generated by an evidence generator or an evidence generating authority using asymmetric cryptographic techniques.
Non-repudiation mechanisms generic to the various non-repudiation services are described first. The different parts of this International Standard provide non-repudiation mechanisms for the following phases of non-repudiation: evidence generation, transfer, storage, retrieval and verification. The non-repudiation mechanisms are then applied to a selection of specific non-repudiation services such as non-repudiation of origin, non-repudiation of delivery, non-repudiation of submission, and non-repudiation of transport. Non-repudiation mechanisms provide protocols for the exchange of non-repudiation tokens specific to each non-repudiation service. Non-repudiation tokens consist of secure envelopes and/or digital signatures and, optionally, of additional data.