demonstrated a theoretical attack which could retrieve the private key from the card within minutes on a standard desktop pc. It has been estimated that the security of the cards will hold up until early 2010 before it becomes a trivial matter to exploit the inherent security vulnerabilities of the RFID based card system. Privacy Users of the system pass their card over a processor both on boarding and departure of any mode of transport using the system. Each SmartRider card is uniquely numbered, and registration is necessary before the card can be used for concession card holders, and is necessary to access many of the advertised features for other users though is not compulsory. The registration process requires filling in a form providing Transperth with the passenger's full name, address, date of birth, SmartRider card number and password. Usage data is stored both on the card and centrally by Transperth and provides users of the system the capability to check and review recent usage by either visiting a designated Information Kiosk or online via the Transperth website. The police have the potential to use SmartRider card data as an investigative tool, and use of this feature overseas is dramatically increasing. In London, where the RFID-technology Oyster Card is in use, there were 243 police requests made in total as of March 2006. Design The system has been criticised for usability issues in general system, website and top-up machine design. Costs Criticism has been directed at the cost to users of the SmartRider system compared to its predecessor, the MultiRider. While the MultiRider could be bought as a 40-ride ticket for a 25% discount, a lesser 20% discount can now only be obtained by paying by direct debit, which can take up to 3 weeks to activate. A 10% discount is available for all other methods of payment. This was raised in Parliament by Liberal MP Katie Hodson-Thomas, who claimed that passengers would end up paying $324 more a year for public transport under SmartRider. In February 2006, The West Australian reported criticism by trial users who claimed that their failure to tag off, either by accidentally forgetting to do so or due to a non-working machine, resulted in a four-zone fare being charged to the SmartRider regardless of distance travelled. However, Transperth has maintained that the default fare is "equal to the cash fare on the assumed basis that