New paper by Ross Anderson: “Can We Fix the Security Economics of Federated Authentication?“:
There has been much academic discussion of federated authentication, and quite some political manoeuvring about ‘e-ID’. The grand vision, which has been around for years in various forms but was recently articulated in the US National Strategy for Trustworthy Identities in Cyberspace (NSTIC), is that a single logon should work everywhere . You should be able to use your identity provider of choice to log on anywhere; so you might use your driver’s license to log on to Gmail, or use your Facebook logon to file your tax return. More restricted versions include the vision of governments of places like Estonia and Germany (and until May 2010 the UK) that a government-issued identity card should serve as a universal logon. Yet few systems have been fielded at any scale.
In this paper I will briefly discuss the four existing examples we have of federated authentication, and then go on to discuss a much larger, looming problem. If the world embraces the Apple vision of your mobile phone becoming your universal authentication device so that your phone contains half-a dozen credit cards, a couple of gift cards, a dozen coupons and vouchers, your AA card, your student card and your driving license, how will we manage all this? A useful topic for initial discussion, I argue, is revocation. Such a phone will become a target for bad guys, both old and new. What happens when someone takes your phone off you at knifepoint, or when it gets infested with malware? Who do you call, and what will they do to make the world right once more?