[TLS] Using both External PSK and (EC)DH in TLS 1.3

2016-12-22 Thread Russ Housley
I want to make sure that it is possible to mix PSK with (EC)DH as a protection against the discovery of a quantum computer. I recognize that the WG does not want to tackle this topic in the base specification; however, the following text in Section 4.1.1 makes this difficult to do so in a compa

Re: [TLS] Using both External PSK and (EC)DH in TLS 1.3

2016-12-22 Thread David Benjamin
It's possible I'm misunderstanding your message here (I'm a little confused by the mention of combining normal certificate authentication with an external PSK), but TLS 1.3 already allows doing both PSK and (EC)DH. That's the psk_dhe_ke mode, rather than the psk_ke mode. It's signaled by the server

Re: [TLS] Using both External PSK and (EC)DH in TLS 1.3

2016-12-22 Thread Joseph Salowey
Does you implementation allow a PSK to be used along with certificate based authentication? On Thu, Dec 22, 2016 at 2:12 PM, David Benjamin wrote: > It's possible I'm misunderstanding your message here (I'm a little > confused by the mention of combining normal certificate authentication with >

Re: [TLS] Using both External PSK and (EC)DH in TLS 1.3

2016-12-22 Thread Russ Housley
David: Yes, it does allow both, but the authentication is unclear when both are in play. The last bullet implies that certificate authentication only comes into play when there is no PSK. So, if there is a PSK, the identity associated with it seems to trump whatever is in the certificate. As

Re: [TLS] Using both External PSK and (EC)DH in TLS 1.3

2016-12-22 Thread Eric Rescorla
On Thu, Dec 22, 2016 at 2:28 PM, Joseph Salowey wrote: > Does you implementation allow a PSK to be used along with certificate > based authentication? > There is presently no way to negotiate this in TLS 1.3. I have been assuming that if we decide we want this we would add a psk_auth_mode extens