Introduction to the Persona Model

04 Oct 2005 I think there is no "Identity" for a physical person in the digital world. How could a computer know who I am? It's just a computer, after all.

My computer holds a data entity that describes some parts of me. It also knows that if somethink causes to press the keys in the right sequence (enter password on a keyboard), then it probably is the object that is described by this data entity. It also knows that it should associate every excuted process and created file with that data entity. And it can also claim to other computers that somethink described by this data entity caused current action.

But does the computer know me? It looks like we, people, are quite "virtual" objects from the computer viewpoint. We cannot exist in the digital world. Only the data entities that describe us can realy exist there.

I will call these data entities "personae" or "personas", as they are our masks in the digital world. And if you take a closer look at the digital world as it works today, you will notice plenty of personae there: accounts, profiles, database records, LDAP entries, sessions, ...

You as a single individual may maintain several personae that are based on your physical being: an employee persona, a citizen persona, a community persona. And you may also maintain several other personae: a role-playing-game persona or non-real community persona. (Remeber that old one: "On the Internet nobody knows you are a dog"?)

Personae propagate to ther systems using claims. One system claims that the persona, as the system believes, has certain characteristics. Other system may evaluate the claims and build its own persona based on that information. You can also link personae together. That's what domains and realms do. And federation also, but in quite a different way.

I've put together an essay that describes this model. You can find it at nLight web page. There is also a longer elaboration of the persona linking, but that was not published yet (it is being reviewed since May).

The model is a work in progress. Any comments welcomed. Please use the contact form to leave me a message.