Patent ID: 7039617

Claim:
A method for operating an electronic purse system to provide personal access to one or more access stations in said system, each of said access stations containing a secure access module and being arranged to load or debit a purse card with an amount of money, said system having a system key for protecting transactions and for verifying that a secure access module and a purse card belong to the same system, said method being performed by one of said secure access modules and comprising the steps of: defining a float ID for each of a plurality of user groups that are supported by said system; defining a single system key that is shared by said plurality of user groups; and upon presentation of a purse card to an access station containing said secure access module: determining whether a key on said purse card matches said single system key; determining whether a float ID read from said purse card specifies a user group supported by said system; and completing a transaction with said purse card only if the key on the purse card matches said single system key and the float ID read from the purse card specifies a user group supported by said system.