Security services and security mechanisms
Non-repudiation

Secure communications need to integrate a service in charge of generating digital evidence in order to resolve disputes arisen in case of network errors or entities' misbehaviour when digital information is exchanged between two or more participants.

Non-repudiation is the security service that uses these evidences to provide protection against denial by one of the entities involved in a communication of having participated in all or part of that communication.

Non repudiation is the security service to guarantee that the sender of a message cannot later deny having sent the message and that the recipient cannot deny having received the message.

It includes non-repudiation of origin (i.e. proof that the message was sent by the specific party) and non-repudiation of reception (i.e. proof that the message was received by the specific party).

The typical protection mechanisms are: notarization, timestamp, digital signatures and confirmation services.