authentication

In computing, system for certifying the origin of an electronic communication. In the non-electronic world, a handwritten signature authenticates a document, for example a contract, as coming from a particular person. In the electronic world, encryption systems provide the same function via digital signatures and other techniques.

In public-key cryptography, for example, the ability to decrypt a message with a particular user's public key authenticates the message as coming from that user and no one else. Authentication is an essential requirement for electronic commerce.