[TLS] Re: [External⚠️] Re: [EXT] Re: [EXTERNAL] Re: Dual certificates in TLS proposal

[Watson Ladd <[e-mail]>]

On Wed, Jun 18, 2025 at 5:00 PM Yaroslav Rosomakho
<[e-mail]> wrote:
>
> Because it won’t require running a zoo of PKIs. Ideally just two - classic and pure PQ with eventual convergence on the latter.

Why is it impossible to have a classical and pure PQ PKI, and then
have clients signal support for which to show, to enable transition?
This is what we already have, and already has worked.

>
> -yaroslav
>
> On 19 Jun 2025, at 01:51, Blumenthal, Uri - 0553 - MITLL <[e-mail]> wrote:
>
> And you want a composite signature in TLS - why?
> —
> Regards,
> Uri
>
> Secure Resilient Systems and Technologies
> MIT Lincoln Laboratory
>
> On Jun 18, 2025, at 19:48, Yaroslav Rosomakho <[e-mail]> wrote:
>
> 
> On Thu, Jun 19, 2025 at 1: 33 AM Watson Ladd <watsonbladd@ gmail. com> wrote: On Wed, Jun 18, 2025, 4: 30 PM Yaroslav Rosomakho <yrosomakho@ zscaler. com> wrote: One of the key use cases is to simplify PKI architectures for closed environments
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> On Thu, Jun 19, 2025 at 1:33 AM Watson Ladd <[e-mail]> wrote:
>>
>> On Wed, Jun 18, 2025, 4:30 PM Yaroslav Rosomakho <[e-mail]> wrote:
>>>
>>> One of the key use cases is to simplify PKI architectures for closed environments that will have to deal with a mix of clients.
>>>
>>> Transition from RSA to ECDSA required two end-entity certificates and did not have to touch the rest of the certificate chain.
>>
>>
>> Why does this draft make that simpler?
>>
>> It envisions two separate chains. Same as with using the existing negotiating mechanisms.
>>
>
> With a composite certificate approach two separate chains are sufficient only if one serves classic-only clients and composite-only clients that are compatible with a given choice of composites. PQ-only clients or clients with other opinions about components of PQ/T will require an additional chain for every variation.
>
>
> -yaroslav
>
>
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