Right, that’s exactly what I was thinking. Thanks for fleshing it out. -Tim
From: Aaron Gable <[email protected]> Sent: Friday, August 11, 2023 1:47 PM To: Tim Hollebeek <[email protected]> Cc: Russ Housley <[email protected]>; IETF ACME <[email protected]> Subject: Re: [Acme] Internet-Draft: PQC Algorithm negotiation in ACME Oh that's fun, I like that idea. Making it explicit: Introduce a new identifier type "keypair-KEM". When included in a newOrder request, an identifier of that type would have a value that is the full KEM public key. The Server would then create an Authorization for that identifier, and the Challenge object(s) for that Authorization would contain a ciphertext encrypted to that public key. The Client would then POST to the Challenge URL with a body containing the plaintext (very similar to the non-empty Challenge POST body from draft-ietf-acme-onion-00's onion-csr-01 validation method). Very similar flows could be adopted for other keypair types as well. The only additional requirement I see is that, especially for those other keypairs, the CA would have to verify that the public key in the CSR matches the public key provided in the Order. Aaron On Fri, Aug 11, 2023 at 10:26 AM Tim Hollebeek <[email protected]<mailto:[email protected]>> wrote: I was thinking (a) happens in (1), and (c) happens in (3), but I haven't done enough (or any) analysis to see if that can be made to work. The other possibility is to treat PoP as another identifier that must be validated in (2), which might be cleaner. Dunno. Treating it as a validation step instead of a finalization step feels more correct anyway. "The use of ACME for other identifiers will require further specification in order to describe how these identifiers are encoded in the protocol and what types of validation challenges the server might require." This might be one of those times. -Tim > -----Original Message----- > From: Russ Housley <[email protected]<mailto:[email protected]>> > Sent: Friday, August 11, 2023 1:20 PM > To: Tim Hollebeek > <[email protected]<mailto:[email protected]>> > Cc: IETF ACME <[email protected]<mailto:[email protected]>> > Subject: Re: [Acme] Internet-Draft: PQC Algorithm negotiation in ACME > > Tim: > > I understand the large organization problem. With KEM PoP, you need these > things in order: > > a) subject provides the KEM public key > > b) server forms a ciphertext using the provided KEM public key and sends it > to the subject > > c) the subject recovers the plaintext using the KEM private key and send > it to > the server > > These do not fit cleanly into the ACME order finalization process, which is > just > one round trip. > > Russ > > > > On Aug 11, 2023, at 1:10 PM, Tim Hollebeek > > <[email protected]<mailto:[email protected]>> > wrote: > > > > Returning it as part of the protocol makes more sense to me than trying to > stuff it into DNS. One could imagine including it as part of some sort of > extension in the CSR that optionally proves possession (if desired), for > example. > > > > One of the challenges we often have with issuance protocols is that the part > of the organization that controls the keys and is setting up servers is often > different from the part of organization that can change DNS, and they can't > always coordinate their work for reasons that should be familiar to anyone > with the misfortune of ever working for a large company. > > > > -Tim > > > >> -----Original Message----- > >> From: Acme <[email protected]<mailto:[email protected]>> On Behalf > >> Of Russ Housley > >> Sent: Friday, August 11, 2023 12:57 PM > >> To: IETF ACME <[email protected]<mailto:[email protected]>> > >> Subject: Re: [Acme] Internet-Draft: PQC Algorithm negotiation in ACME > >> > >> Thinking about KEM PoP in the context of ACME. The subject must > >> provide the KEM subject public key as part of the certificate > >> request. A new challenge could be defined (for example, dns-kem-00) > >> where the token is a KEM ciphertext, and the subject needs to put the > >> corresponding plaintext in to DNS. This proves possession of the KEM > >> private key as well as administrative control over the domain. > >> > >> This does not totally match the flow in RFC 8555, which is: > >> > >> 1. Submit an order for a certificate to be issued > >> > >> 2. Prove control of any identifiers requested in the certificate > >> > >> 3. Finalize the order by submitting a CSR > >> > >> 4. Await issuance and download the issued certificate > >> > >> The KEM public key would need to be provided in step 1. I guess it > >> is not a big deal for the KEM public key to be repeated in step 3, as > >> long as the ACME server checked for a match. > >> > >> Russ > >> > >> _______________________________________________ > >> Acme mailing list > >> [email protected]<mailto:[email protected]> > >> https://www.ietf.org/mailman/listinfo/acme _______________________________________________ Acme mailing list [email protected]<mailto:[email protected]> https://www.ietf.org/mailman/listinfo/acme
_______________________________________________ Acme mailing list [email protected] https://www.ietf.org/mailman/listinfo/acme
