So, we’ve now
illustrated how to establish three levels of personal identity. In addition,
we’ve seen how to blend our historical identification systems with a digital
system based on biometrics. We can engage in interactions under the guise of
any of these levels of identity. By clearly specifying the levels, all parties
to an interaction have the same expectations of interpretation. Perhaps more
important, with these well-defined levels, our transcendent personal devices
can be expected to better act on our behalves. Finally, no matter the level of
personal identity used, the interaction process is the same. Let’s briefly
review the steps of the interaction.
The first step
we will term the overture. As with a
play, this step is prelude to the main action. It entails bringing the
supplicant and the sentinel in contact such that they both decide that they
wish to enter into the authentication protocol proper. The actions that occur
during the overture suggest that either side can first take the initiative in
the process. The sentinel may first notice the approach of the supplicant and
issue a preliminary challenge: “Halt, who goes there?” Alternatively, the
supplicant can take the initiative: “Hello the house!” Following this very
preliminary exchange, the sentinel can then begin the formal authentication
procedure: “Advance and be recognized!” The supplicant then responds with an
initial assertion of identity: “I’m Jane Doe.” Within the cyberspace
interaction, we would actually like to give the somewhat stilted assertion: “I
am the anchored persona, Jane Doe.”
In essence, we’ve
codified an exchange that might occur between two strangers meeting in an
isolated location where the intentions of either can range from benign to
threatening. For the etiquette of a transcendent personal device, this
corresponds to the range of actions from a person plugging an identification
token into an apparently dormant system versus an application reaching a point
where it needs token services and issuing an order to “Insert Your Token.” We’ve
gone a bit overboard in discussing the overture stage because this is an area
where operational models of different systems can diverge rather significantly;
so, it is useful to model this well such that the two parties can land on their
feet no matter how they get started.
The remaining
stages are typically understood in a generic sense, but they can vary a great
deal in the details. Once a supplicant name is asserted during the overture
then the next step is that of marker
acquisition. This step is aimed at gathering a marker from the supplicant
and providing it to the sentinel. The only real new wrinkle here, from a
conceptualization viewpoint, is recognizing that these successive stages may be
pursued recursively in order to achieve an adequate trust level among all the
elements of the two systems. For example, the two sides might first seek to
recognize that each is presenting or using trusted equipment and then
subsequently seek to establish trust in the differential identity of the supplicant
as well as that of the sentinel. This is particularly important because, for
most current token based systems, the token needs to trust the sensors on the
sentinel through which the marker is acquired.
The marker to be
acquired can run the full gamut of approaches to uniquely authenticate
differential identity. It might consist of having the marked party select a
series of objects from a list, providing a graphical password. Or, it might
entail actually entering a text password or a personal identification number.
On a more complex plane, it might entail capturing a facial image of the
supplicant or perhaps an image of their iris pattern or one or more
fingerprints. In the extreme, it might entail capturing a swab of bodily fluids
from which DNA can be obtained. Once the marker is acquired, it can be compared
by the sentinel to a marker template that was gathered from the supplicant on
enrollment.
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