Non-repudiation

Non-repudiation is the concept of ensuring that a contract, especially one agreed to via the Internet, cannot later be denied by one of the parties involved. In today's global economy, where face-to-face agreements are often not possible, non-repudiation is becoming extremely important to commerce.

With regards to digital security, non-repudiation means that it can be verified that the sender and the recipient were, in fact, the parties who claimed to send or receive the message, respectively.