December 06, 2003

What is Pseudonymity?

In a recent Declan misinterpretation, discussed over on Larry Lessig''s Blog at the definition of pseudonymity was rasied [1].

Larry Lessig proposes that pseudonymity is a mechanism that hides a real identity, short of presentation of (say) a "warrant". I disagree with this definition, and it's certainly not the one that I've seen having dealt with these things in the last decade or so.

Pseudonymity is achieved when an entity is created that can clearly tie its activities together into one individuality. A Pseudonym, or nym for short, has individuality, distinction, a personality, and a name.

In contrast, Anonymity lacks these facets. It is achieved when it is not possible to tie one activity to another of the same entity.

In further contrast, we have the Real Person, who is fully identified down to the single human being [2]. That means we have three states for source of any event: anonymity, pseudonymity, and identified. And, there are two entities: nyms, and real persons [3].

Larry's definition presupposes the existence of the real person behind every nym.

In practice, that's not what happens - a pseudonymous account at Hotmail or Yahoo includes a bunch of details that may or may not point at a person behind that account. The existence of that information doesn't imply whether there are zero, one, or many people behind that account, and it doesn't imply that last week's people are next week's people. But, it does imply that a single email from the account can be related to all other emails from the same nym.

For example, it has been the case that groups of people have shared the same nym in order to maintain a prolific personality. In a sense, the nym is the set of all emails from that same entity. Their personality is derived solely from the words in those emails, whereas the personality of a real person includes more information outside their words.

In contrast, when an entity (either nymous or real) writes two different emails anonymously, there is no connection between them. A crucial feature of anonymity is that it lacks "distinctive character, individuality, factors of recognition, personality."

Nyms have all that. Nyms have names, they have personalities, built over many actions. They just lack a handle back to any single human.

Why is it crucial to get the distinction clear? Because of systems design: Systems built without a full appreciation of nymity migrate into real identity systems, and repeat the existing failures. Systems built with nymity at their core are capable of solving new and interesting challenges that real identity systems will always fail at.


[1] How does one organise this trackback ping thing then?

[2] What is the proper term for a Real Person and their singular Identity in this context? I don't know.

[3] For sake of brevity, I skip over the interesting application of this to "legal persons" such as corporations.

Posted by iang at December 6, 2003 10:52 AM | TrackBack