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This problem has been solved. The idea is to use identity federation, claims-based authorisation, and a privacy-enhancing technology that lets the subject deter

This problem has been solved. The idea is to use identity federation, claims-based authorisation, and a privacy-enhancing technology that lets the subject determine which claims to share with a resource provider. Such a system can verify identity without divulging that identity. For instance, when you buy beer you need to prove you're over 18. The barman doesn't need to know your name, address, what vehicle classes you're licensed to drive, or age. All the barman needs is to know that you're over 18. The reason nobody uses it is that it's unpalatable to identity and resource providers alike. Imagine a world where you could buy anything without the seller ever knowing who you are. Or your bank not knowing what you bought. Or your identity provider (government) not knowing where you're using your authN credential. The tech community doesn't like it because even though it's open source, it's from Microsoft. And that it uses XML. So we keep on using broken identity systems like Persona and OAUTH. http://research.microsoft.com/en-us/projects/u-prove/ http://research.microsoft.com/en-us/projects/u-prove/

icebraining 13y ago
U-Prove is interesting, but it doesn't solve the problem I posed. With our current ID cards, the identity provider is already ignorant where I use it. All they did was sign the certificate in my card, and now third-parties can check the chain without informing the IdP about me. The problem with U-Prove is that it still relies on a single identity provider. What happens when, by incompetence or malice, the State revokes your identity? And assuming that you can voluntarily revoke identities (e.g. if they're stolen) and not lose you bank accounts and so, there must be some way of proving that your new identity is just a new version of the old one. So, what prevents the IdP from creating fake identities that allow them to pass as you? The idea of applying Convergence would be to decouple the identity from that single provider, and I don't see how U-Prove helps with that.
- Spearchucker 13y ago
  U-Prove can use any number of identity providers. It can even create a single new token assembled from pieces (claims, or inferred claims like age) of multiple identity providers. Decoupling an identity from a provider invalidates the identity. Identities have value because of the providers' relationships with subjects. It's up to the resource provider to establish trust relationships with other identity providers.
  - icebraining 13y ago
    Fair enough, it seems I have to do some reading on that proposal. Still, what happens when a single IdP invalidates their claims? Is the whole token invalidated?
    - Spearchucker 13y ago
      The token is invalidated, as with any identity system. That's how it should work. Think certificate revocation lists, for example. The identity provider has to be able to revoke certs, or the entire trust model would fall apart.

icebraining 13y ago

U-Prove is interesting, but it doesn't solve the problem I posed. With our current ID cards, the identity provider is already ignorant where I use it. All they did was sign the certificate in my card, and now third-parties can check the chain without informing the IdP about me. The problem with U-Prove is that it still relies on a single identity provider. What happens when, by incompetence or malice, the State revokes your identity? And assuming that you can voluntarily revoke identities (e.g. if they're stolen) and not lose you bank accounts and so, there must be some way of proving that your new identity is just a new version of the old one. So, what prevents the IdP from creating fake identities that allow them to pass as you? The idea of applying Convergence would be to decouple the identity from that single provider, and I don't see how U-Prove helps with that.

Spearchucker 13y ago
U-Prove can use any number of identity providers. It can even create a single new token assembled from pieces (claims, or inferred claims like age) of multiple identity providers. Decoupling an identity from a provider invalidates the identity. Identities have value because of the providers' relationships with subjects. It's up to the resource provider to establish trust relationships with other identity providers.
- icebraining 13y ago
  Fair enough, it seems I have to do some reading on that proposal. Still, what happens when a single IdP invalidates their claims? Is the whole token invalidated?
  - Spearchucker 13y ago
    The token is invalidated, as with any identity system. That's how it should work. Think certificate revocation lists, for example. The identity provider has to be able to revoke certs, or the entire trust model would fall apart.