[TLS] Enforcing Protocol Invariants

2018-06-12 Thread David Benjamin
Hi all, Now that TLS 1.3 is about done, perhaps it is time to reflect on the ossification problems. TLS is an extensible protocol. TLS 1.3 is backwards-compatible and may be incrementally rolled out in an existing compliant TLS 1.2 deployment. Yet we had problems. Widespread non-compliant servers

[TLS] CH padding extension

2018-06-12 Thread Christopher Wood
Hi folks, In Section 4.2 of the latest TLS 1.3 draft [1], the padding(21) extension is restricted to the CH and no other handshake messages. Another plausible spot for this extension is in the Certificate message. Specifically, although we're encrypting this message, we may not want to reveal its

Re: [TLS] CH padding extension

2018-06-12 Thread Kyle Nekritz
Since the Certificate message is sent in an encrypted record, the normal record padding mechanism (section 5.4) can be used, rather than sending the padding as actual handshake data. -Original Message- From: TLS On Behalf Of Christopher Wood Sent: Tuesday, June 12, 2018 1:41 PM To: Su

Re: [TLS] CH padding extension

2018-06-12 Thread Christopher Wood
On Tue, Jun 12, 2018 at 10:55 AM Kyle Nekritz wrote: > > Since the Certificate message is sent in an encrypted record, the normal > record padding mechanism (section 5.4) can be used, rather than sending the > padding as actual handshake data. Of course, and that requires padding on the fly and

Re: [TLS] CH padding extension

2018-06-12 Thread David Benjamin
On Tue, Jun 12, 2018 at 2:01 PM Christopher Wood < christopherwoo...@gmail.com> wrote: > On Tue, Jun 12, 2018 at 10:55 AM Kyle Nekritz wrote: > > > > Since the Certificate message is sent in an encrypted record, the normal > record padding mechanism (section 5.4) can be used, rather than sending

Re: [TLS] CH padding extension

2018-06-12 Thread Christopher Wood
On Tue, Jun 12, 2018 at 11:32 AM David Benjamin wrote: > > On Tue, Jun 12, 2018 at 2:01 PM Christopher Wood > wrote: >> >> On Tue, Jun 12, 2018 at 10:55 AM Kyle Nekritz wrote: >> > >> > Since the Certificate message is sent in an encrypted record, the normal >> > record padding mechanism (sect

Re: [TLS] CH padding extension

2018-06-12 Thread David Benjamin
On Tue, Jun 12, 2018 at 2:44 PM Christopher Wood < christopherwoo...@gmail.com> wrote: > On Tue, Jun 12, 2018 at 11:32 AM David Benjamin > wrote: > > > > On Tue, Jun 12, 2018 at 2:01 PM Christopher Wood < > christopherwoo...@gmail.com> wrote: > >> > >> On Tue, Jun 12, 2018 at 10:55 AM Kyle Nekrit

Re: [TLS] CH padding extension

2018-06-12 Thread Christopher Wood
Got it — thanks for the clarification! I agree with your conclusion assuming we do not want to make an incompatible wire format change. However, if we’re willing to budge on that, I think it’s worth including. I’m curious to hear what others think. Best, Chris On Jun 12, 2018, 11:48 AM -0700, D

Re: [TLS] CH padding extension

2018-06-12 Thread Roelof duToit
You could use the existing Certificate padding mechanism. Which mechanism?! The one in this paragraph: For maximum compatibility, all implementations SHOULD be prepared to handle potentially extraneous certificates and arbitrary orderings from any TLS version, with the exception of the end-ent

Re: [TLS] Enforcing Protocol Invariants

2018-06-12 Thread Jana Iyengar
I'm emerging from lurking to just say this: I think this is a fantastic idea, and thank you for doing it. FWIW and IMO, you're better off summarizing the codepoints you are using and planning to use on a wiki somewhere instead of in registries, given the timescales and the lifetime of these codepoi