doc

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Changed
 
 - The `read_ledger.py` tool now has a `--quiet` option which avoids printing anything per-transaction, as well as other performance improvements, which should make it more useful in verifying the integrity of large ledgers.
+- COSE signatures now set a kid that is a hex-encoded SHA-256 of the DER representation of the key used to produce them (#6703).
 
 ## [6.0.0-dev8]
 

cddl/ccf-merkle-tree-cose-signature.cddl

@@ -13,7 +13,7 @@ unprotected-headers = {
 
 protected-headers = {
   &(alg: 1) => int,                     ; signing algoritm ID, as per RFC8152
-  &(kid: 4) => bstr,                    ; signing key hash
+  &(kid: 4) => bstr,                    ; Opaque key identifier, hex-encoded SHA-256 of the public key encoded as DER.
   &(cwt: 15) => cwt-map,                ; CWT claims, as per RFC8392
   &(vds: 395) => int,                   ; verifiable data structure, as per COSE Receipts (draft) RFC (https://datatracker.ietf.org/doc/draft-ietf-cose-merkle-tree-proofs/)
   "ccf.v1" => ccf-map                   ; a set of CCF-specific parameters