re: ECDH.
They are compatible. i wouldn't specify the mechanism here specifically, Instead I would say it would be "generate according to ... " and list all three generation mechanisms. The resulting keys from these will all be usable in a KEM. We could decide that we only want one here. We'll discuss it today.
RE: ML-KEM
If there isn't an internal KDF which selects the key length, we should drop LENGTH and the mechanism should return the natural length of the returned key for the given parameter set.
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Robert Relyea
Principle Software Engineer
Red Hat
Mountain View CA
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Original Message:
Sent: 05-22-2024 19:30
From: Darren Johnson
Subject: KEM algs draft 5 uploaded
Hi Bob,
I had a couple more questions on draft 5 as well.
The section on ECDH and ECDH-C states that "For C_Encapsulate, an ephemeral key pair is generated.". The current specification supports two key-pair generation mechanisms for CKK_EC key pairs. But it isn't clear which mechanism is supposed to get used to generate the ephemeral key pair. I believed we discussed this on the last call, but I can't remember what the conclusion was. Do we leave it up to the implementation? Do we make it specifiable by the caller? I don't think we should leave it undefined.
The section on the ML-KEM key agreement still states "For C_Encapsulate and C_Decapsulate the length controls the output of the ML-KEM internal KDF". The internal KDF was part of the Kyber specification, but was removed in the FIPS 203 draft, and I haven't heard any indication that it will be added back in in the final version of FIPS 203. I think in our earlier email exchanges that you suggested that "we will need to add a KDF mechanism", but there hasn't been any updates related to this. Did you have other intentions?
Thanks
Darren
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Darren Johnson
THALES
Original Message:
Sent: 05-22-2024 16:19
From: Jonathan Schulze-Hewett
Subject: KEM algs draft 5 uploaded
Hi Bob,
A nit, section 1.4's Table 11 heading is incorrect and mentions Diffie-Hellman rather than ML-KEM.
More substantially, I think that Table 11 should not have Wrap and Unwrap checked for the ML-KEM mechanism and that the ML-KEM mechanism section should not include K-PKE. I think that was your intention, but the current draft still has it in there. If we want K-PKE support then I think it should be a different mechanism not a different behavior of the ML-KEM mechanism based on which function is called.
Sincerely,
Jonathan
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Jonathan Schulze-Hewett
Information Security Corporation
Oak Park IL
Original Message:
Sent: 05-15-2024 19:31
From: Robert Relyea
Subject: KEM algs draft 5 uploaded
Document Name: KEM algs draft 5 Description This includes updates from Darren and Jonathan's comments. It looks like most of Darren's comments were against an earlier draft and were already fixed. The other change was the removal of CPAKE Download Latest Revision Public Download Link Submitter: Mr. Robert Relyea Group: OASIS PKCS 11 TC Folder: Working Drafts Date submitted: 2024-05-15 23:31:12
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Robert Relyea
Principle Software Engineer
Red Hat
Mountain View CA
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