Thursday, July 08, 2004

Trust No one.

Aside from being the mantra of one of my favorite television serials of all times, the statement "trust no one" also serves as an interesting mathematical limit to the concept of authentication. Specifically, I am willing to state with some confidence that I trust, absolutely, all claims made by no one. You see, "no one" doesn’t tend to make many claims, and therefore does nothing to stretch their credibility. While seemingly nonsensical, or at best very "Zen", I urge the reader to think through this statement a little further.

As previously mentioned, the various perspectives of authentication form a multidimensional space in which the "trust" one places in an identity claim can be evaluated. That, however, is only the beginning of the problem. The next problem is to determine just how "evaluable" such a space might be. It does no good to provide a theoretical model which has no practical way of being resolved.

By demonstrating (anecdotally) that there is a definition of the upper bound (I trust, in the absolute, "no one") we have established one of the criteria of evaluability. Next, it is easy to postulate that the there is a minimum, as well: "even if I truly believed you are who you claim to be, I would place no trust in you." This, however, creates an interesting consequence: If we have a guaranteed minimum value (absolutely no trust) which we can place on an identity claim and a guaranteed maximum value (perfect trust) on another claim, then we have both upper and lower bounds on our results. This means we can normalize any evaluation result to any range of values we want: like, say,

**0…1**. This is an important conclusion that supports the tractability of any claim that meets these criteria. Further, if our formula is continuous, it would then be differentiable, which would facilitate the evaluation of trust over time.

How, then, do we begin to produce a formula that is able to take these various aspects and provides a useful evaluation of the identity? And how does this tie in with the concept of trust? Ah, fodder for another post.