Patent ID: 8791794

Claim:
A method for obtaining from an item information source item information relating to an item, said item having associated therewith an item identification means providing item identification information and an RFID response means arranged to provide a predetermined RFID response on being subjected to a currently applicable RFID trigger signal; said method comprising: establishing from said item identification means item identification information; using said item identification information to determine from said item information source a currently applicable RFID trigger signal for said RFID response means; subjecting said RFID response means to said currently applicable RFID trigger signal; receiving a predetermined RFID response from said RFID response means; and using said predetermined RFID response to obtain item information from said item information source; wherein the RFID response means is arranged to generate a new currently applicable RFID trigger signal and a new predetermined RFID response associated therewith following the subjecting of said RFID response means to said currently applicable RFID trigger signal; wherein the RFID response means and the item information source are each arranged to generate the new currently applicable RFID trigger signal in step with one another by performing at least one of the following: selecting and using a next member from a predetermined sequence of currently applicable RFID trigger signals; applying a predetermined one-way function or hash-function to the currently applicable RFID trigger signal; and applying a pseudorandom function to the currently applicable RFID trigger signal; and wherein the RFID response means and the item information source are each arranged to generate the predetermined RFID response associated with the new currently applicable RFID trigger signal in step with one another by performing at least one of the following: selecting and using a next member from a predetermined sequence of predetermined RFID responses; applying a predetermined one-way function or hash-function to an existing predetermined RFID response; and applying a pseudorandom function to an existing predetermined RFID response.