Non-repudiation (also spelled nonrepudiation) is a data security attribute that demonstrates that a certain party performed a particular action at some point in the past. This means that at any future point, a party cannot reject (or repudiate) that a certain action was performed by themselves.
Although there is some similarity to the attribute of authenticity, the two are not the same. This is because one may fulfill the requirements of authenticity, but keep no records of the event, which would mean no way to fulfill the requirements of non-repudiation. This means that one can have authenticity without non-repudiation, but not non-repudiation without authenticity.
Non-repudiation can also be considered to be an important legal concept, and not fulfilled entirely by technical requirements.
Last updated: 17 October 2017