Authentication
From Erights
Definition
Given one end of a communication channel, an authentication procedure establishes which principal is probably at the other end.
Notes
Often the communication channel is implicit. For example, authenticating the originator of a document is covered by the above definition, if we view the document as representing one end of a communication channel from its originator.
The ability to perform authentication enables accountability.
Examples
Banknotes, for example, can also be viewed as "one end of a communcation channel". Banknote states that its holder has certain amount of money. Banknotes are valid, if that statement is claimed by the central bank. Authentication of the banknote reveals whether this is the case.