Yes, confirming high level direction.

I support registering string / integer values for "alg" that fully specify
how to use HPKE.

I object to registering "partial" or "polymorphic" values for "alg", that
require extra stuff to be useful.

OS


On Thu, Jul 20, 2023 at 8:27 AM Hannes Tschofenig <[email protected]>
wrote:

> I agree with all of that but the first step is to confirm the high-level
> direction.
>
> Once the high level direction is confirmed, I am sure we can quickly work
> out the details. You, Carsten and others have proposed solutions already.
>
> We need to make this first step asap. If we wait till the IETF meeting we
> need to do the confirmation on the mailing list pushing the decision making
> into the holiday period...
>
>
> Ciao
>
> Hannes
>
>
> Am 20.07.2023 um 14:39 schrieb Orie Steele:
>
> There needs to be an integer / string value for alg.
>
> It needs to work with keys and envelopes.
>
> It needs to express an HPKE suite, which is a combination of details which
> become irrelevant once named properly.
>
> It's not that these details don't matter, it's that the average developer
> doesn't need to know them to use HPKE.
>
> Here are the APIs a developer needs:
>
> 1. K = Gen(alg)
> 2. CT = Encrypt(alg, k.Public, PT)
> 3. PT = Decrypt (alg, k.Private, CT)
>
> Notice that when alg specifies HPKE properly, a single integer or string
> is enough to satisfy these.
>
> In the case that the key representation carries the alg, it can be ommited
> from 2 and 3.
>
> This is also the case if you discover alg separately from the key.
>
> The goal is make discovery and use of hpke as simple as possible.
>
> You just compare a string or integer that a recipient supports, to a list
> of strings or integers you support.
>
> This comparison tells you all you need, to use HPKE, with parties that
> support it.
>
> There are other ways to do this.
>
> They are not as good, and they break conventions.
>
> OS
>
>
>
>
> On Thu, Jul 20, 2023, 6:10 AM Hannes Tschofenig <[email protected]>
> wrote:
>
>> Hi Carsten,
>>
>>
>> part of the problem is that quickly get lost in details while we should
>> actually stay at the high level. The disagreement is at the highest level.
>>
>>
>> This is not even a new topic: the concept of algorithm registration in
>> security protocol is around for 30 or so years.
>>
>>
>> Ciao
>>
>> Hannes
>>
>>
>>
>> Am 20.07.2023 um 12:21 schrieb Carsten Bormann:
>> > Hi Hannes,
>> >
>> > I’m afraid this is even more confusing than your last note.
>> >
>> >> On 2023-07-20, at 11:48, Tschofenig, Hannes <hannes.tschofenig=
>> [email protected]> wrote:
>> >>
>> >> Hi Mike,
>> >>
>> >> Here is the question the working group is facing.
>> >>
>> >> Should there
>> >>      • be a single value associated with the combination of KEM, KDF,
>> and AEAD, or
>> > “The” combination?  Each combination?  All combinations?
>> > (Which means there is an additional data item containing the specific
>> combination.)
>> >
>> >>      • individual values for each of them.
>> > Individual *data items*, with values defined for each to be used in
>> combination for those additional data items?
>> >
>> >> The former design is often called ciphersuite.
>> > Is “former” (a)?  If (a) says “each specific combination”, I can parse
>> that.
>> >
>> >> We used (a) in earlier versions of the COSE-HPKE draft (see, for
>> example, draft-ietf-cose-hpke-01 ) and (b) in later versions of the draft
>> (see, for example, draft-ietf-cose-hpke-05).
>> >>
>> >> Based on my assessment of the feedback from the group, there is a
>> preference to switch back to the ciphersuite approach.
>> > Right.
>> >
>> > (And I have made a proposal to more or less solve the biggest problem
>> with ciphersuites, but that is somewhat orthogonal.)
>> >
>> > Grüße, Carsten
>> >
>> >
>> > _______________________________________________
>> > COSE mailing list
>> > [email protected]
>> > https://www.ietf.org/mailman/listinfo/cose
>>
>> _______________________________________________
>> COSE mailing list
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>>
>
> _______________________________________________
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>
>

-- 


ORIE STEELE
Chief Technology Officer
www.transmute.industries

<https://transmute.industries>
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