Re: [MLS] Question regarding ClientInitKey message format

Richard Barnes <rlb@ipv.sx> Wed, 02 October 2019 21:38 UTC

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From: Richard Barnes <rlb@ipv.sx>
Date: Wed, 2 Oct 2019 22:38:00 +0100
Message-ID: <CAL02cgQ330S8gsUXwbPhhU_i7_cdaEmKKLHcff3SbLc=2tsEAQ@mail.gmail.com>
To: Pascal Junod <cryptopathe@gmail.com>
Cc: Messaging Layer Security WG <mls@ietf.org>
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Subject: Re: [MLS] Question regarding ClientInitKey message format
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In addition to what Benjamin said, I think you've misunderstood the meaning
of the length indications.  The lengths indicate the size in *bytes*, not
in *entries*.  So the ciphersuites field can hold 128 2-byte ciphersuites,
and the init_keys can hold however many public keys will fit in 65535 bytes.

But as Benjamin said, this has all been obsoleted by more recent changes.

--Richard

On Wed, Oct 2, 2019 at 4:17 PM Pascal Junod <cryptopathe@gmail.com>; wrote:

> Hello,
>
> I am new to that list, so please accept my apologies in advance for any
> wrong doings with respect to the list etiquette !
>
> I am currently reading draft-07 (Aug. 13, 2019) and something is not
> clear to me with respect to the ClientInitKey format defined in section
> 7. The array of ciphersuites cipher_suites is expected to have a length
> of 0 to 255 ciphersuites, while the array of public keys init_keys is
> expected to have between one and 65535 public keys. At the same time, an
> above paragraph says that the init_array MUST have the same length as the
> cipher_suites array. Shouldn't both of them having a length <1,255> ? Or
> what did I misunderstand?
>
> Best,
>
> Pascal
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