Re: [TLS] [DTLS] ACK's for post-handshake authentication requests

Thanks. This seems like a good improvement. I have filed
https://github.com/tlswg/dtls13-spec/issues/128 to track it.

On Fri, Mar 27, 2020 at 8:29 AM Hanno Becker <Hanno.Becker@arm.com> wrote:

> I have a minor comment on DTLS 1.3 draft 37.
>
> On the topic of sending ACKs, the draft recommends:
>
> ```
> ACKs SHOULD NOT be sent for other complete
> flights because they are implicitly acknowledged by the receipt of
> the next flight, which generally immediately follows the flight.
> ```
>
> I wonder if the case of post-handshake authentication should be
> explicitly mentioned as a potential exception to this rule, since
> the TLS 1.3 RFC explicitly mentions that responses to
> `CertificateRequest` may be delayed in some contexts:
>
> ```
> Note: Because client authentication could involve prompting the user,
> servers MUST be prepared for some delay, including receiving an
> arbitrary number of other messages between sending the
> CertificateRequest and receiving a response.
> ```
>
> In this case, it would be beneficial to immediately explicitly ACK
> the `CertificateRequest` message even though it is also implicitly
> acked through the eventual response via the `Certificate` message.
>
> Regards,
> Hanno
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