src/main.cpp

@@ -3491,6 +3491,42 @@ bool CVerifyDB::VerifyDB(CCoinsView *coinsview, int nCheckLevel, int nCheckDepth
     return true;
 }
 
+bool GetProofForName(const CBlockIndex* pindexProof, const std::string& name, CNCCTrieProof& proof)
+{
+    AssertLockHeld(cs_main);
+    if (!chainActive.Contains(pindexProof))
+    {
+        return false;
+    }
+    CCoinsViewCache coins(pcoinsTip);
+    CNCCTrieCache trieCache(pnccTrie);
+    CBlockIndex* pindexState = chainActive.Tip();
+    CValidationState state;
+    for (CBlockIndex *pindex = chainActive.Tip(); pindex && pindex->pprev && pindexState != pindexProof; pindex=pindex->pprev)
+    {
+        boost::this_thread::interruption_point();
+        CBlock block;
+        if (!ReadBlockFromDisk(block, pindex))
+        {
+            return false;
+        }
+        if (pindex == pindexState && (coins.DynamicMemoryUsage() + pcoinsTip->DynamicMemoryUsage()) <= nCoinCacheUsage)
+        {
+            bool fClean = true;
+            if (!DisconnectBlock(block, state, pindex, coins, trieCache, &fClean))
+            {
+                return false;
+            }
+            pindexState = pindex->pprev;
+        }
+        if (ShutdownRequested())
+            return false;
+    }
+    assert(pindexState == pindexProof);
+    proof = trieCache.getProofForName(name);
+    return true;
+}
+
 void UnloadBlockIndex()
 {
     LOCK(cs_main);

src/main.h

@@ -167,6 +167,8 @@ FILE* OpenBlockFile(const CDiskBlockPos &pos, bool fReadOnly = false);
 FILE* OpenUndoFile(const CDiskBlockPos &pos, bool fReadOnly = false);
 /** Translation to a filesystem path */
 boost::filesystem::path GetBlockPosFilename(const CDiskBlockPos &pos, const char *prefix);
+/** Get a cryptographic proof that a name maps to a value **/
+bool GetProofForName(const CBlockIndex* pindexProof, const std::string& name, CNCCTrieProof& proof);
 /** Import blocks from an external file */
 bool LoadExternalBlockFile(FILE* fileIn, CDiskBlockPos *dbp = NULL);
 /** Initialize a new block tree database + block data on disk */

src/ncctrie.cpp

@@ -1307,11 +1307,6 @@ CNCCTrieProof CNCCTrieCache::getProofForName(const std::string& name) const
         if (cachedNode != cache.end())
             current = cachedNode->second;
         hashMapType::const_iterator cachedHash = cacheHashes.find(currentPosition);
-        uint256 nodeHash;
-        if (cachedHash != cacheHashes.end())
-            nodeHash = cachedHash->second;
-        else
-            nodeHash = current->hash;
         CNodeValue val;
         bool fNodeHasValue = current->getBestValue(val);
         uint256 valHash;
@@ -1332,7 +1327,7 @@ CNCCTrieProof CNCCTrieCache::getProofForName(const std::string& name) const
                 nextCurrent = itChildren->second;
             }
         }
-        nodes[currentPosition] = CNCCTrieProofNode(child_chars, fNodeHasValue, valHash, nodeHash);
+        nodes[currentPosition] = CNCCTrieProofNode(child_chars, fNodeHasValue, valHash);
         current = nextCurrent;
         if (current == NULL)
             break;
@@ -1343,11 +1338,6 @@ CNCCTrieProof CNCCTrieCache::getProofForName(const std::string& name) const
         if (cachedNode != cache.end())
             current = cachedNode->second;
         hashMapType::const_iterator cachedHash = cacheHashes.find(name);
-        uint256 nodeHash;
-        if (cachedHash != cacheHashes.end())
-            nodeHash = cachedHash->second;
-        else
-            nodeHash = current->hash;
         fNameHasValue = current->getBestValue(nameVal);
         uint256 valHash;
         if (fNameHasValue)
@@ -1365,7 +1355,7 @@ CNCCTrieProof CNCCTrieCache::getProofForName(const std::string& name) const
             std::pair<std::string, CNCCTrieProofLeafNode> leaf = getLeafNodeForProof(name, itChildren->first, itChildren->second);
             leafNodes[leaf.first] = leaf.second;
         }
-        nodes[name] = CNCCTrieProofNode(child_chars, fNameHasValue, valHash, nodeHash);
+        nodes[name] = CNCCTrieProofNode(child_chars, fNameHasValue, valHash);
     }
     else
     {

src/ncctrie.h

@@ -205,11 +205,10 @@ class CNCCTrieProofNode
 {
 public:
     CNCCTrieProofNode() {};
-    CNCCTrieProofNode(std::vector<unsigned char> children, bool hasValue, uint256 valHash, uint256 nodeHash) : children(children), hasValue(hasValue), valHash(valHash), nodeHash(nodeHash) {};
+    CNCCTrieProofNode(std::vector<unsigned char> children, bool hasValue, uint256 valHash) : children(children), hasValue(hasValue), valHash(valHash) {};
     std::vector<unsigned char> children;
     bool hasValue;
     uint256 valHash;
-    uint256 nodeHash;
 };
 
 class CNCCTrieProofLeafNode

src/rpcncctrie.cpp

@@ -269,3 +269,121 @@ UniValue getclaimsfortx(const UniValue& params, bool fHelp)
     }
     return ret;
 }
+
+UniValue proofToJSON(const CNCCTrieProof& proof)
+{
+    UniValue result(UniValue::VOBJ);
+    UniValue nodes(UniValue::VARR);
+    for (std::map<std::string, CNCCTrieProofNode>::const_iterator itNode = proof.nodes.begin(); itNode != proof.nodes.end(); ++itNode)
+    {
+        UniValue node(UniValue::VOBJ);
+        node.push_back(Pair("name", itNode->first));
+        UniValue children(UniValue::VARR);
+        for (std::vector<unsigned char>::const_iterator itChildren = itNode->second.children.begin(); itChildren != itNode->second.children.end(); ++itChildren)
+        {
+            children.push_back(*itChildren);
+        }
+        node.push_back(Pair("children", children));
+        if (itNode->second.hasValue)
+        {
+            node.push_back(Pair("valueHash", itNode->second.valHash.GetHex()));
+        }
+        nodes.push_back(node);
+    }
+    result.push_back(Pair("nodes", nodes));
+    UniValue leafNodes(UniValue::VARR);
+    for (std::map<std::string, CNCCTrieProofLeafNode>::const_iterator itLeafNode = proof.leafNodes.begin(); itLeafNode != proof.leafNodes.end(); ++itLeafNode)
+    {
+        UniValue leafNode(UniValue::VOBJ);
+        leafNode.push_back(Pair("name", itLeafNode->first));
+        leafNode.push_back(Pair("nodeHash", itLeafNode->second.nodeHash.GetHex()));
+        leafNodes.push_back(leafNode);
+    }
+    result.push_back(Pair("leafNodes", leafNodes));
+    if (proof.hasValue)
+    {
+        result.push_back(Pair("txhash", proof.txhash.GetHex()));
+        result.push_back(Pair("nOut", (int)proof.nOut));
+    }
+    return result;
+}
+
+UniValue getnameproof(const UniValue& params, bool fHelp)
+{
+    if (fHelp || (params.size() != 1 && params.size() != 2))
+        throw std::runtime_error(
+            "getnameproof\n"
+            "Return the cryptographic proof that a name maps to a value\n"
+            "or doesn't.\n"
+            "Arguments:\n"
+            "1. \"name\"             (string) the name to get a proof for\n"
+            "2. \"blockhash\"        (string, optional) the hash of the block\n"
+            "                                            which is the basis\n"
+            "                                            of the proof. If\n"
+            "                                            none is given, \n"
+            "                                            the latest block\n"
+            "                                            will be used.\n"
+            "Result: \n"
+            "{\n"
+            "  \"nodes\" : [       (array of object) full nodes (i.e.\n"
+            "                                        those which lead to\n"
+            "                                        the requested name)\n"
+            "    \"name\" : \"node name\" (string) The name of the node\n"
+            "    \"children\" : [ (array of numeric) the characters\n"
+            "                                        corresponding to\n"
+            "                                        the children of\n"
+            "                                        this node\n"
+            "      \"child\"     (numeric) a 0-255 number referring to\n"
+            "                              a child node of this node\n"
+            "      ]\n"
+            "    \"valueHash\"   (string, if exists) the hash of this\n"
+            "                                        node's value, if\n"
+            "                                        it has one\n"
+            "    ]\n"
+            "  \"leaf_nodes\" : [  (array of object) leaf nodes (i.e.\n"
+            "                                        those which do not\n"
+            "                                        lead to the requested\n"
+            "                                        name but nonetheless\n"
+            "                                        contribute to the proof\n"
+            "    \"name\" : \"node name\" (string) the name of the node\n"
+            "    \"nodeHash\" : \"hash\"  (string) the hash of the node\n"
+            "    ]\n"
+            "  \"txhash\" : \"hash\" (string, if exists) the txid of the\n"
+            "                                            claim which controls\n"
+            "                                            this name, if there\n"
+            "                                            is one.\n"
+            "  \"nOut\" : n,         (numeric) the nOut of the claim which\n"
+            "                                  controls this name, if there\n"
+            "                                  is one.\n"
+            "  }\n"
+            "}\n");
+
+    LOCK(cs_main);
+    std::string strName = params[0].get_str();
+    uint256 blockHash;
+    if (params.size() == 2)
+    {
+        std::string strBlockHash = params[1].get_str();
+        blockHash = uint256S(strBlockHash);
+    }
+    else
+    {
+        blockHash = chainActive.Tip()->GetBlockHash();
+    }
+
+    if (mapBlockIndex.count(blockHash) == 0)
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
+
+    CBlockIndex* pblockIndex = mapBlockIndex[blockHash];
+    if (!chainActive.Contains(pblockIndex))
+        throw JSONRPCError(RPC_INTERNAL_ERROR, "Block not in main chain");
+
+    if (chainActive.Tip()->nHeight > (pblockIndex->nHeight + 10))
+        throw JSONRPCError(RPC_INTERNAL_ERROR, "Block too deep to generate proof");
+
+    CNCCTrieProof proof;
+    if (!GetProofForName(pblockIndex, strName, proof))
+        throw JSONRPCError(RPC_INTERNAL_ERROR, "Failed to generate proof");
+
+    return proofToJSON(proof);
+}

src/rpcserver.cpp

@@ -386,6 +386,7 @@ static const CRPCCommand vRPCCommands[] =
     { "nametrie",           "gettotalclaims",         &gettotalclaims,         true  },
     { "nametrie",           "gettotalvalueofclaims",  &gettotalvalueofclaims,  true  },
     { "nametrie",           "getclaimsfortx",         &getclaimsfortx,         true  },
+    { "nametrie",           "getnameproof",           &getnameproof,           true  },
 };
 
 CRPCTable::CRPCTable()

src/rpcserver.h

@@ -247,6 +247,7 @@ extern UniValue gettotalclaimednames(const UniValue& params, bool fHelp);
 extern UniValue gettotalclaims(const UniValue& params, bool fHelp);
 extern UniValue gettotalvalueofclaims(const UniValue& params, bool fHelp);
 extern UniValue getclaimsfortx(const UniValue& params, bool fHelp);
+extern UniValue getnameproof(const UniValue& params, bool fHelp);
 
 // in rest.cpp
 extern bool HTTPReq_REST(AcceptedConnection *conn,

src/test/ncctrie_tests.cpp

@@ -1418,30 +1418,33 @@ BOOST_AUTO_TEST_CASE(ncctrienode_serialize_unserialize)
     BOOST_CHECK(n1 == n2);
 }
 
-bool verify_proof(CNCCTrieProof proof, uint256 rootHash, const std::string& name)
+bool get_node_hash(const std::string& name, const std::string& currentPosition, const std::string::const_iterator itName, CNCCTrieProof& proof, uint256& nodeHash)
 {
-    for (std::string::const_iterator itName = name.begin(); itName != name.end(); ++itName)
-    {
-        std::string currentPosition(name.begin(), itName);
     std::map<std::string, CNCCTrieProofNode>::const_iterator itNode = proof.nodes.find(currentPosition);
     if (itNode == proof.nodes.end())
     {
-            return currentPosition != "" && !proof.hasValue;
+        return false;
+    }
+    if (name == currentPosition && itName != name.end())
+    {
+        return false;
     }
     std::vector<unsigned char> vchToHash;
+    bool haveNextNode = false;
     for (std::vector<unsigned char>::const_iterator itChildren = itNode->second.children.begin(); itChildren != itNode->second.children.end(); ++itChildren)
     {
         vchToHash.push_back(*itChildren);
         std::stringstream nextPosition;
         nextPosition << currentPosition << *itChildren;
-            if (*itChildren == *itName)
+        if (name != currentPosition && *itChildren == *itName)
         {
-                std::map<std::string, CNCCTrieProofNode>::const_iterator itChildNode = proof.nodes.find(nextPosition.str());
+            uint256 childNodeHash;
-                if (itChildNode == proof.nodes.end())
+            if (!get_node_hash(name, nextPosition.str(), itName + 1, proof, childNodeHash))
             {
                 return false;
             }
-                vchToHash.insert(vchToHash.end(), itChildNode->second.nodeHash.begin(), itChildNode->second.nodeHash.end());
+            haveNextNode = true;
+            vchToHash.insert(vchToHash.end(), childNodeHash.begin(), childNodeHash.end());
         }
         else
         {
@@ -1453,47 +1456,24 @@ bool verify_proof(CNCCTrieProof proof, uint256 rootHash, const std::string& name
             vchToHash.insert(vchToHash.end(), itChildNode->second.nodeHash.begin(), itChildNode->second.nodeHash.end());
         }
     }
+    if (name != currentPosition)
+    {
+        if (!haveNextNode && proof.hasValue)
+        {
+            return false;
+        }
         if (itNode->second.hasValue)
         {
             vchToHash.insert(vchToHash.end(), itNode->second.valHash.begin(), itNode->second.valHash.end());
         }
-        CHash256 hasher;
+    }
-        std::vector<unsigned char> vchHash(hasher.OUTPUT_SIZE);
+    else
-        hasher.Write(vchToHash.data(), vchToHash.size());
+    {
-        hasher.Finalize(&(vchHash[0]));
+        if (proof.hasValue != itNode->second.hasValue)
-        uint256 calculatedHash(vchHash);
-        if (calculatedHash != itNode->second.nodeHash)
         {
             return false;
         }
-        if (currentPosition == "" && calculatedHash != rootHash)
+        if (proof.hasValue)
-        {
-            return false;
-        }
-    }
-    std::map<std::string, CNCCTrieProofNode>::const_iterator itNode = proof.nodes.find(name);
-    if (itNode == proof.nodes.end())
-    {
-        return name != "" && !proof.hasValue;
-    }
-    std::vector<unsigned char> vchToHash;
-    for (std::vector<unsigned char>::const_iterator itChildren = itNode->second.children.begin(); itChildren != itNode->second.children.end(); ++itChildren)
-    {
-        vchToHash.push_back(*itChildren);
-        std::stringstream nextPosition;
-        nextPosition << name << *itChildren;
-        std::map<std::string, CNCCTrieProofLeafNode>::const_iterator itChildNode = proof.leafNodes.find(nextPosition.str());
-        if (itChildNode == proof.leafNodes.end())
-        {
-            return false;
-        }
-        vchToHash.insert(vchToHash.end(), itChildNode->second.nodeHash.begin(), itChildNode->second.nodeHash.end());
-    }
-    if (itNode->second.hasValue != proof.hasValue)
-    {
-        return false;
-    }
-    if (itNode->second.hasValue)
         {
             uint256 valHash = getOutPointHash(proof.txhash, proof.nOut);
             if (valHash != itNode->second.valHash)
@@ -1502,22 +1482,22 @@ bool verify_proof(CNCCTrieProof proof, uint256 rootHash, const std::string& name
             }
             vchToHash.insert(vchToHash.end(), valHash.begin(), valHash.end());
         }
+    }
     CHash256 hasher;
     std::vector<unsigned char> vchHash(hasher.OUTPUT_SIZE);
     hasher.Write(vchToHash.data(), vchToHash.size());
     hasher.Finalize(&(vchHash[0]));
     uint256 calculatedHash(vchHash);
-    if (calculatedHash != itNode->second.nodeHash)
+    nodeHash = calculatedHash;
-    {
-        return false;
-    }
-    if (name == "" && calculatedHash != rootHash)
-    {
-        return false;
-    }
     return true;
 }
 
+bool verify_proof(CNCCTrieProof proof, uint256 rootHash, const std::string& name)
+{
+    uint256 computedRootHash;
+    return get_node_hash(name, "", name.begin(), proof, computedRootHash) && rootHash == computedRootHash;
+}
+
 BOOST_AUTO_TEST_CASE(ncctrievalue_proof)
 {
     int block_counter = 0;