authenticator

Noun

 * 1)  One who, or something which, authenticates, as:
 * 2) An app that uses  to prove someone's identity to a network connection.
 * 3) A  that shows something to be authentic.
 * 4)  A person employed to check the accuracy and realism of a script.

Translations

 * German: Beglaubiger, Beglaubigerin