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Re: Solutions to the NASCAR problem?

From: Anders Rundgren <anders.rundgren.net@gmail.com>
Date: Mon, 23 Nov 2015 06:40:45 +0100
To: David Chadwick <d.w.chadwick@kent.ac.uk>, public-credentials@w3.org
Message-ID: <5652A6DD.5080700@gmail.com>
On 2015-11-22 18:53, David Chadwick wrote:
>
>
> On 22/11/2015 16:33, Anders Rundgren wrote:
>> On 2015-11-22 17:10, David Chadwick wrote:
>>> Hi Anders
>>
>> Hi David,
>>
>> <snip>
>>
>>>>> The user sends the consumer SOP public key to the issuer and the issuer
>>>>> assigns the attribute to that.
>>>>
>>>> I think you lost me here, at least with respect to the NASCAR problem.
>>>
>>> This is because the user does not go to any third party to authenticate
>>> to a site. A new key pair is generated for the site, and this
>>> authenticates the user each time he calls. Note however that FIDO does
>>> not provide any identity or authz information, just an authn key, which
>>> is why we need to add this functionality using issuers.
>>
>> It is this sending of the consumer public key to issuer by the user which
>> I don't quite understand :(
>
> The user can prove possession of all the public keys his device has
> issued. This is how he authenticates. The consumer only knows it is the
> user at the other end of the connection because a challenge from the
> consumer was signed by the private key corresponding to the user's
> consumer public key.
>
> Now if the consumer receives an attribute signed by an issuer, it proves
> that the issuer issued it, but not who it belongs it. By using the
> consumer public key as the ID of the user, the consumer now knows that
> the user it has authenticated is the righful owner of the attributes.

Pardon me for being unclear.  I understand the concept on this level,
I was only curious about the user processes needed for this to work.

Anyway, I have considerable faith in the augmented key model where
issuer-defined attributes are used to enhance a key's usage.

The "only" problem is how to deal with such keys on the Web without
creating [close to] unresolvable privacy, usability, or security problems.

Regards
Anders

>
> regards
>
> David
>>
>> Anders
>>
Received on Monday, 23 November 2015 05:41:23 UTC

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