Hi Isobe-san, Hannes, I believe this draft is necessary. I support it.
Best, AJITOMI Daisuke 2023年5月29日(月) 3:45 Ilari Liusvaara <[email protected]>: > On Sun, May 28, 2023 at 05:23:11PM +0200, Hannes Tschofenig wrote: > > I agree regarding OKP and HSS-LMS key types, Ilari. > > > > Kohei and I wanted to get an initial version out to the group to see > > what others in the group think. Hence, we kept is short & simple. > > > > Some (bad) attempt at text (edited from text in the draft, needs > further editing): > > > 3. COSE Key Thumbprint > > The thumbprint of a COSE Key MUST be computed as follows: > > 1. Construct a COSE_Key structure (see Section 7 of [RFC9052]) > containing only the required parmeters representing the key. This > specification describes what those required parameters are and what, > if necessary, the data types are. > > 2. Encode the COSE_Key into byte string using the Core Deterministic > Encoding described in Section 4.2.1 of [RFC8949]. > > 3. Hash the bytes from step (2) with a cryptographic hash function H. > For example, SHA-256 [RFC6234] may be used as a hash function. The > resulting value is the COSE Key Thumbprint with H of the COSE_Key. > The details of this computation are further described in subsequent > sections. > > > 4. Required COSE Key Parameters > > Only the public key parameters of a key's representation are used when > computing its COSE Key Thumbprint value. This section summarizes these > parameters. > > The "kty" (label: 1) parameter MUST be present for all key types and the > values found in the IANA COSE Key Types registry MUST be used. Other > parameters depend on the key type. The subsection below list the required > parameters for commonly used key types (in order). > > > 4.1. OKP > > OKP keys (value: 1) have the following parameters: > > * "kty" label: 1 value: 1 > * "crv" label: -1 value: int/tstr > * "x" label: -2 value: bstr > > > 4.2. EC2 > > EC2 keys (value: 2) have the following parameters: > > * "kty" label: 1 value: 2 > * "crv" label: -1 value: int/tstr > * "x" label: -2 value: bstr > * "y" label: -3 value: bstr > > Note that for interoperability, uncompressed representation MUST be > used. Hence, the parameter "y" is bstr. A compressed key representation > MUST be decompressed before thumbprint calculation. > > > 4.3. RSA > > RSA keys (value: 3) have the following parameters: > > * "kty" label: 1 value: 3 > * "n" label: -1 value: bstr > * "e" label: -2 value: bstr > > > 4.4. Symmetric > > Symmetric keys do not have thumbprints. > > > 4.5. HSS-LMS > > HSS-LMS keys (value: 5) have the following parameters: > > * "kty" label: 1 value: 5 > * "pub" label: -1 value: bstr > > > > > -Ilari > > _______________________________________________ > COSE mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/cose >
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