<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On 26 Mar 2009, at 13:57, Leif Nixon wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div><br>Well, some banks over here have a authentication system that uses a<br>hardware crypto token with a keypad. You use it for a challenge-response<br>procedure to log in to the Internet banking site - nothing new so far -<br>but you also use it to sign (using challenge-response) each bunch of<br>transactions you perform on the banking site. And - this is the key<br>point - to sign the transactions you actually enter certain parts of the<br>transaction data (like the total amount to transfer) into the crypto token.<br><br>Even with total control over the client PC, it's real hard for an<br>attacker to do anything really evil in that setting.<br><br></div></blockquote><div><br></div>But check this analysis of the UK version, which seems to be almost exactly as described...<br><div><br></div><a href="http://www.cl.cam.ac.uk/~sjm217/papers/fc09optimised.pdf">http://www.cl.cam.ac.uk/~sjm217/papers/fc09optimised.pdf</a></div><div><br></div><div apple-content-edited="true"> <div><p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">--</font></p> <p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">-- Jim</font></p> <p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">--</font></p> <p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">James Cownie <<a href="mailto:jcownie@cantab.net">jcownie@cantab.net</a>></font></p> <br class="Apple-interchange-newline"></div> </div><br></body></html>