Greetings all, This e-mail is to point to some resources and give some background information on the TBD Numerical Identifiers in the HSS work item. Essentially, the NIST SP on Stateful Hash-based Signatures [3] introduced parameter sets that were not defined previously in the CFRG approved RFCs [1, 2]. In particular, not for HSS [2]. Parameter sets that exist in both [2] and [3] are consistent with each other and have Numerical Identifiers assigned to them (and are included in both documents). However, the HSS parameter sets that were introduced in the Special Publication do not yet have Numerical Identifiers assigned to them. Further, it is not the responsibility of NIST to assign those Identifiers, rather it is the responsibility of the CFRG. The following quote is from an e-mail correspondence with NIST: "According to RFC 8554 additions to the registry for LMS must 'have first been reviewed by the IRTF Crypto Forum Research Group (CFRG).' There is an Internet Draft that specifies the additional parameter sets,
https://datatracker.ietf.org/doc/draft-fluhrer-lms-more-parm-sets/ , however, I do not recall seeing any recent discussion of this document on the CFRG mail list." From that same e-mail thread: "We plan to ask the CFRG to complete their review and for their approval at the next IETF meeting." I have not heard anything since then (from the CFRG or NIST) on the state of progress for these Identifiers. For completeness, the following is directly from the SP [3]: "Extensions to the XDR syntax in Section 3.3 of [2] needed to support the parameter sets defined in Sections 4.2 through 4.4 of this document are specified in Appendix A. The numeric identifiers for these parameter sets are marked as ‘TBD’ since they had not yet been assigned at the time this document was published. Once they are assigned, the numeric identifiers may be found at
https://www.iana.org/assignments/leighton-micali-signatures/leighton-micali-signatures.xhtml ." Note, that the page linked above has not been updated since late 2019. I hope this helps! Best regards, and Happy New Year, Philip Lafrance [1] RFC 8391 (XMSS/XMSS-MT):
https://tools.ietf.org/html/rfc8391 [2] RFC 8554 (LMS/HSS):
https://tools.ietf.org/html/rfc8554 [3] NIST SP 800-208
https://csrc.nist.gov/publications/detail/sp/800-208/final -- Philip Lafrance Standards Manager Mobile: +1.226.750.2439
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