Abstract: An authentication device (100) for use with electronic security devices and user authentication systems is disclosed. The authentication device includes a data store (104) for storing plural secret keys, each secret key associated with a corresponding service, a service selection means (101) for selecting a service from the corresponding services, an authentication code generator (102) for generating, from the secret key associated with the selected service, a one time usable authentication code for communication to an authentication controller associated with the selected service, and an output (106) for outputting the generated authentication code for communication to the authentication controller. A method of authentication a user to a service is also disclosed.

Abstract: A method of authenticating a remote service (104) to a user (102) via a communications network (106) is disclosed. The remote service (104) obtains a service authentication code that has been generated, using a code generation algorithm, based on a first secret key. The service authentication code is communicated to the user (102) via the communications network (106) and received, or entered, into an authentication device (106) associated with the user (102). The authentication device (106) then generates, using the same code generation algorithm, an expected code value based on a second secret key and compares the expected code value to the service authentication code. Responsive to the comparison, and in the event that the expected code value correlates with the service authentication code, the authentication device (106) generates a response that indicates to the user (102) the authenticity of the remote service (104).