Protecting the security of an entity by using passcodes is disclosed. A passcode device generates a passcode. In an embodiment, the passcode is generated in response to receipt of user information. The passcode is received by another system, which authenticates the passcode by at least generating a passcode from a passcode generator, and comparing the generated passcode with the received passcode. The passcode is temporary. At a later use a different passcode is generated from a different passcode generator.