Use CBOR wrappers for COSE receipts decoding (#7575)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Amaury Chamayou <amaury@xargs.fr>

Author: 3 people

include/ccf/receipt.h

@@ -142,6 +142,14 @@ namespace ccf
     MERKLE_PROOF_LEAF_LABEL = 1,
     MERKLE_PROOF_PATH_LABEL = 2
   };
+  // NOLINTNEXTLINE(performance-enum-size)
+  enum MerkleProofPathBranch : int64_t
+  {
+    // Values set in
+    // https://github.com/ietf-scitt/draft-birkholz-cose-cometre-ccf-profile
+    LEFT = 0,
+    RIGHT = 1
+  };
   std::optional<std::vector<uint8_t>> describe_merkle_proof_v1(
     const TxReceiptImpl& receipt);
 

src/crypto/openssl/cose_sign.h

@@ -19,6 +19,7 @@ namespace ccf::crypto
   // Standardised: CWT claims map.
   static constexpr int64_t COSE_PHEADER_KEY_CWT = 15;
   // Standardised: verifiable data structure.
+  // https://www.ietf.org/archive/id/draft-ietf-cose-merkle-tree-proofs-18.html#name-cose-header-parameter
   static constexpr int64_t COSE_PHEADER_KEY_VDS = 395;
   static constexpr int64_t COSE_PHEADER_VDS_CCF_LEDGER_SHA256 = 2;
   // Standardised: issued at CWT claim. Value is **PLAIN INTEGER**, as per