What's the difference between an ephemeral key that's reused and a static key?
-Ekr On Mon, Oct 20, 2025 at 5:10 AM John Mattsson <john.mattsson= [email protected]> wrote: > SP 800-227 is already required by FIPS 203 for the use of ML-KEM in > applications. Referencing SP 800-227 directly, rather than just indirectly > through FIPS 203, is not a technical change. > > > > SP 800-227 disallows the use of an ephemeral key in more than one > key-establishment execution. It permits the reuse of static keys, as well > as the reuse of ephemeral keys across multiple key shares, provided that > only one of those shares is used for key establishment. > > John > > > > *From: *Kris Kwiatkowski <[email protected]> > *Date: *Monday, 20 October 2025 at 13:29 > *To: *[email protected] <[email protected]> > *Subject: *[TLS] Re: Working Group Last Call for Post-quantum Hybrid > ECDHE-MLKEM Key Agreement for TLSv1.3 > > Just to be crystal clear - that would be a way to disallow a key reuse in > TLS v1.3 when using MLKEM (as per RS6 in Section 1.3). Correct? > > On 20/10/2025 12:05, John Mattsson wrote: > > Hi, > > I am cornered with the current PR #53 suggesting that SP 800-227 “provides > general guidance”. This is not a correct description. > > > > As stated in FIPS 203, SP 800-227 provides requirements for the use of > ML-KEM in applications. TLS 1.3 is such an application. > > Unless the working group wants to discuss each requirement in detail, I > would suggest just adding: > > ”As stated in FIPS 203 {{FIPS203}}, SP 800-227 {{NIST-SP-800-227}} > provides requirements for the use of ML-KEM in applications.” > > > In general, I think it is very important that IETF follows NIST > requirements when using a NIST algorithms like ML-KEM. > > Cheers, > John > > > https://github.com/tlswg/tls-ecdhe-mlkem/pull/53 > > https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.203.pdf > > > > _______________________________________________ > > TLS mailing list -- [email protected] > > To unsubscribe send an email to [email protected] > > _______________________________________________ > TLS mailing list -- [email protected] > To unsubscribe send an email to [email protected] >
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