COSE signatures over merkle root in the ledger

python/src/ccf/ledger.py

@@ -517,8 +517,7 @@ def add_transaction(self, transaction):
         if COSE_SIGNATURE_TX_TABLE_NAME in tables:
             cose_signature_table = tables[COSE_SIGNATURE_TX_TABLE_NAME]
             cose_signature = cose_signature_table.get(WELL_KNOWN_SINGLETON_TABLE_KEY)
-            signature = json.loads(cose_signature)
-            cose_sign1 = base64.b64decode(signature["sig"])
+            cose_sign1 = base64.b64decode(cose_signature)
             self._verify_root_cose_signature(self.merkle.get_merkle_root(), cose_sign1)
 
         # Checks complete, add this transaction to tree

src/node/history.h

@@ -393,7 +393,7 @@ namespace ccf
       auto cose_sign = crypto::cose_sign1(service_kp, pheaders, root_hash);
 
       signatures->put(sig_value);
-      cose_signatures->put(CoseSignature{cose_sign});
+      cose_signatures->put(cose_sign);
       serialised_tree->put(history.serialise_tree(txid.version - 1));
       return sig.commit_reserved();
     }
@@ -764,7 +764,7 @@ namespace ccf
         root.h.data(), root.h.data() + root.h.size()};
 
       return cose_verifier_cached(raw_cert)->verify_detached(
-        cose_sig->sig, root_hash);
+        cose_sig.value(), root_hash);
     }
 
     std::vector<uint8_t> serialise_tree(size_t to) override

src/service/tables/signatures.h

@@ -61,17 +61,7 @@ namespace ccf
   using SerialisedMerkleTree =
     ccf::kv::RawCopySerialisedValue<std::vector<uint8_t>>;
 
-  struct CoseSignature
-  {
-    std::vector<uint8_t> sig;
-
-    CoseSignature() {}
-
-    CoseSignature(const std::vector<uint8_t>& sig_) : sig(sig_) {}
-  };
-
-  DECLARE_JSON_TYPE(CoseSignature)
-  DECLARE_JSON_REQUIRED_FIELDS(CoseSignature, sig);
+  using CoseSignature = std::vector<uint8_t>;
 
   // Most recent COSE signature is a single Value in the KV
   using CoseSignatures = ServiceValue<CoseSignature>;