Which concept ensures that an action cannot be denied after it has been performed?

The concept that ensures an action cannot be denied after it has been performed is non-repudiation. Non-repudiation provides a guarantee that someone cannot deny the validity of their actions. This is crucial in environments where verification of actions is needed, such as in legal transactions, financial records, or secure communications. It typically involves mechanisms like digital signatures or audit trails, which serve as evidence that an action was taken by a specific individual or entity.

In contrast, authenticity generally refers to the verification that something is genuine or not altered, accountability relates to the obligation of individuals to be answerable for their actions, and accuracy pertains to the correctness and precision of information or data. While all these concepts are important in the context of security, non-repudiation specifically addresses the issue of ensuring that individuals cannot later dispute their involvement in actions that have been recorded or executed.