In data communications, nonrepudiation for a sender ensures that the entity that sends a message cannot later deny having sent it, and for a receiver ensures that the entity that has received a message cannot later deny having received it.

Nonrepudiation is also an essential component in audit data security. A user must not be able to deny having performed an action if it is recorded in the audit record; similarly, a user must not be able to claim to have performed an action if the audit record does not reflect that fact.