Re: Private key possession

[Denis Pinkas <D.Pinkas@xxxxxxxxxxxx>]

Peter Williams wrote:

> >Their document introduces the notion of a certificate counter-signed by
> >the user. In such an architecture a certificate holds two signatures:
> >one from the CA and another one from the user. In this way the user
> >endorses the fact that the CA has issued the certificate. This is a
> >proof that the user not only knows the private key but also accepts the
> >certificate.
> 
> Are you claiming this is a messaging proof/non-repudiation of acceptance,
> service?

No.

> generalised it would say, if I send you a signed message, containing
> your public key bound to some datum, and you countersign that msg, this is
> a mechanism for proof of acceptance of datum, if a validator can find
> a public key value in the (next) inner-signed component which validates the
> outer signature. 


"proof of acceptance of datum" which looks like non repudiation of
acceptance of datum could not be provided by the mechanism you describe.
You are on a different thread here which is far away from the origional
topic that was discussed.


Denis

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