Re: [TLS] TLS 1.3 presentation language

Kazu Yamamoto ( 山本和彦 ) <kazu@iij.ad.jp> Tue, 25 July 2017 06:29 UTC

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From: Kazu Yamamoto <kazu@iij.ad.jp>
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Subject: Re: [TLS] TLS 1.3 presentation language
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Hi Stephen,

Thank you for your nice work.

> Concretely, I think we should make the following changes.
> 1. Replace `length` with `TLSCiphertext.length` in the definition of `TLSCiphertext`.

I agree.

> 2. Replace `Hash.length` with `hash_length` throughout (9 instances).

I agree.

> 3. Change the definition of `select`'s `case` statements to have 0 or more fields (types and names) and remove the optional label.
> 4. Change the `select` example to match the new definition.

I agree if this means 1 or more. (See below)

> 5. Change `Handshake` by adding field names to each `case` statement. (These could all be `body` or they could be unique.)

Would you show me a concrete definition?

> Remove the `body` label.

I agree.

> 6. Delete the `Empty` structure and replace both current uses with the comment `/* Empty */`.

Empty has a long story.

I proposed None (namely Empty) first but it was not accepted:

	https://github.com/tlswg/tls13-spec/issues/630

But when we discussed EarlyDataIndication, this idea came back:

	https://github.com/tlswg/tls13-spec/issues/861

So, people would want to avoid removing Empty again.

--Kazu