A password given to the user for one login session only, which must be used within a certain amount of time. One-time passwords (OTPs) are sent from tech support to people who need help registering or logging into a website. They are also used as a second means of authentication, very often if a person logs in from a new computer (see
two-factor authentication).
As soon as the one-time password (OTP) is entered, it is no longer valid. Also called a time-based one-time password (TOTP), they are used by physical authentication devices (see
authentication token).