Re: Call for Adoption: Secondary Certificate Authentication in HTTP/2

On 11 July 2016 at 11:23, Eric Rescorla <ekr@rtfm.com> wrote:
> 1. It's not possible to force a counterparty to demonstrate that he still
> has control of a given signing key. So, for instance, if you were a server
> and wanted a user to demonstrate that he still had access to the key (like,
> it's in a token and you're authorizing a high value transaction). Because
> what he signs is the same every time, the counterparty can just replay the
> previous assertion.

I think that there is still room for restructuring how the assertions
are made so that integrating a request identifier (which might be
large and random) into the signature is a good idea.

> 2. If you have two certificates with the same key pair, a signature for one
> is a signature for both (for the same reason as #1).

Yes, we should cover the certificate with the signature.  It's
relatively easy to do.  And even if this isn't something that can be
exploited, it keeps this design from diverging too much from TLS
unnecessarily.

Received on Monday, 11 July 2016 04:02:19 UTC