Dave Kearns recently took on the topic of how user-centric and enterprise-centric identity could possibly co-exist in his articles for the Network World Identity Management Newsletter. In his first post, he discussed what the difference between the two is - the need in the Enterprise scenario to have all identity-related transactions tied together from an audit perspective, contrasted with the need in the User-Centric (or personal) scenario to have no ability to tie together the various transactions a person can enter into. In his follow-up post, he discussed how the two, given these diametrically opposite requirements, could co-exist.
Dave postulates that the solution is based in the idea of Digital Personas. If I am reading his thesis correctly, he basically says that a person (an entity) can keep his online transactions un-linkable by using different personas (as represented by different information cards) that are kept separate and distinct at the source (namely the user and his IdP). In this way, common identifiers are avoided (not sure about that, since the most common identifier – an email address – is likely the same across most, if not all, of your personas), and so correlation reports cannot be built that harvest and mine data.
While Dave is clearly working with the constraint of what is possible today (both on a technological and legal footing), I think this solution puts too much of a burden on the end-user, since this requires the user to maintain multiple personas across the various applications he interacts with. In other words, even if the persona I want to present (PII attributes, credit cards, etc) to two different applications is exactly the same, I would need to create two different personas (in effect duplicates) if I want to make sure that there is no linkability. One can see the potential for persona explosion.
This is like saying that a user (who is extremely paranoid and wants no one building a consumer profile by looking at his purchase history) should maintain a different credit card (in effect tens or a few hundred) for every merchant he interacts with. That is comletely impractical. But just like there is no recourse today for consumers in this arena (the SSN, home address information, etc that every credit card record has enables complete linking, and results in the massive databases that telemarketers thrive and live on), it seems that there are no legal and technological solutions enabling the consumer to use the same persona while guaranteeing non-linkability. It’s an interesting problem that I think needs to be addressed by the identity community, because if it isn’t, linking of our online identities will happen (whether we want it or not), because the burden of maintaining multiple personas is just too much work, and user habits will prevail (just like it does in the matter of username-passwords).