A mobile terminal is equipped for SMS payment and service authentication
with a remote transaction provider. The remote provider uses common
secrets & a seed in a keyed Hash Machine Address Code (HMAC) executing a
Message Digest Algorithm to generate a list of authentication token
(username-password) for the purchase of services an/or goods. The common
secrets and seed are shared with local redemption devices which also
generate the list of authentication token. A subscriber conducts payment
with the remote transaction provider and receives an authentication token
corresponding to the purchased service. The subscriber provides the
authentication token to the redemption device which compares the
authentication token with sets of valid authentication tokens generated
by the redemption terminal. If the comparison indicates a match, the
redemption device provides the service to the subscriber.