Re: [TLS] Closing on PSS. PR#1114

[Nikos Mavrogiannopoulos <[e-mail]>]

On Mon, 2017-12-04 at 17:24 -0800, Eric Rescorla wrote:
> Hi folks,
> 
> I've put together a PR that attemps to address the PSS issue.
> 
> See:
> https://github.com/tlswg/tls13-spec/pull/1114
> 
> 
> Because there are platforms which don't have any support for PSS in
> the cert validator, at all, it seems like we MUST be able to express
> the following:
> 
> 1. I accept PSS in CV, but nowhere in certificates, and the SPKI
>    MUST be of type rsaEncryption (because this is what Chrome
>    can do on some platforms).
> 
> Going forward, we want to be able to express:
> 
> 2. I accept PSS in CV *and* everywhere in the certificate chain
>    (otherwise PSS certificates are dead)
> 
> 3. I accept EdDSA in CV but not for signing certificates
>    (note that this is subtly different from the PSS case because
>    you would need an EdDSA SPKI)
> 
> 4. I accept EdDSA in CV and everywhere in the cert chain

I do not see why specific platform considerations should lead such a
major protocol change, at the cost of the platforms which can
accomodate the requirements. I believe that such major moves for
compatibility for specific platforms should be explicitly expressed in
the WG charter.

regards,
Nikos