On 10/03/2003 01:26 PM, R. A. Hettinga wrote: > > It seems to me that perfect pseudonymity *is* anonymity.
They're not quite the same thing; see below.
> Frankly, without the ability to monitor reputation, you don't have > ways of controlling things like transactions, for instance. It's just > that people are still mystified by the concept of biometric > is-a-person identity, which strong cryptography can completely > divorce from reputation.
We agree that identification is *not* the issue, and that lots of people are confused about this.
I'm not sure "reputation" is exactly the right concept either; the notion of "credentials" is sometimes better, and the operating-systems folks speak of "capabilities".
There are three main possibilities: -- named (unique static handle) -- pseudonymous (dynamic handles) -- anonymous (no handle all)
Sometimes pseudonyms are more convenient than having no handle at all. It saves you the trouble of having to re-validate your credentials at every micro-step of the process (whatever the process may be).
Oftentimes pseydonyms are vastly preferable to a static name, because you can cobble up a new one whenever you like, subject to the cost of (re)establishing your credentials from scratch.
The idea of linking (bidirectionally) all credentials with the static is-a-person identity is a truly terrible idea. It dramatically *reduces* security. Suppose Jane Doe happens to have the following credentials -- Old enough to buy cigarettes. -- Has credit-card limit > $300.00 -- Has credit-card limit > $3000.00 -- Has car-driving privileges. -- Has commercial pilot privileges. -- Holds US citizenship. -- Holds 'secret' clearance.
When Jane walks into a seedy bar, someone can reasonably ask to verify her "old-enough" credential. She might not want this query to reveal her exact age, and she might *really* not want it to reveal her home address (as many forms of "ID" do), and she might *really* *really* not want it to reveal all her other credentials and capabilities.
*) There is an exploding epidemic of "ID" theft. That is a sure sign that people keep confusing capability --> identity and identity --> capabilities.
*) There are those who want us to have a national ID-checking infrastructure as soon as possible. They think this will increase security. I think it is a giant step in the wrong direction.
*) Reputation (based on a string of past interactions) is one way, but not the only way, to create a credential that has some level of trust.
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We need a practical system for anonymous/pseudonymous credentials. Can somebody tell us, what's the state of the art? What's currently deployed? What's on the drawing boards?
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