Add RPC call to generate and verify merkle blocks

src/rpcclient.cpp

@@ -79,6 +79,7 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "sendrawtransaction", 1 },
     { "gettxout", 1 },
     { "gettxout", 2 },
+    { "gettxoutproof", 0 },
     { "lockunspent", 0 },
     { "lockunspent", 1 },
     { "importprivkey", 2 },

src/rpcrawtransaction.cpp

@@ -9,6 +9,7 @@
 #include "init.h"
 #include "keystore.h"
 #include "main.h"
+#include "merkleblock.h"
 #include "net.h"
 #include "rpcserver.h"
 #include "script/script.h"
@@ -193,6 +194,119 @@ Value getrawtransaction(const Array& params, bool fHelp)
     return result;
 }
 
+Value gettxoutproof(const Array& params, bool fHelp)
+{
+    if (fHelp || (params.size() != 1 && params.size() != 2))
+        throw runtime_error(
+            "gettxoutproof [\"txid\",...] ( blockhash )\n"
+            "\nReturns a hex-encoded proof that \"txid\" was included in a block.\n"
+            "\nNOTE: By default this function only works sometimes. This is when there is an\n"
+            "unspent output in the utxo for this transaction. To make it always work,\n"
+            "you need to maintain a transaction index, using the -txindex command line option or\n"
+            "specify the block in which the transaction is included in manually (by blockhash).\n"
+            "\nReturn the raw transaction data.\n"
+            "\nArguments:\n"
+            "1. \"txids\"       (string) A json array of txids to filter\n"
+            "    [\n"
+            "      \"txid\"     (string) A transaction hash\n"
+            "      ,...\n"
+            "    ]\n"
+            "2. \"block hash\"  (string, optional) If specified, looks for txid in the block with this hash\n"
+            "\nResult:\n"
+            "\"data\"           (string) A string that is a serialized, hex-encoded data for the proof.\n"
+        );
+
+    set<uint256> setTxids;
+    uint256 oneTxid;
+    Array txids = params[0].get_array();
+    BOOST_FOREACH(Value& txid, txids) {
+        if (txid.get_str().length() != 64 || !IsHex(txid.get_str()))
+            throw JSONRPCError(RPC_INVALID_PARAMETER, string("Invalid txid ")+txid.get_str());
+        uint256 hash(uint256S(txid.get_str()));
+        if (setTxids.count(hash))
+            throw JSONRPCError(RPC_INVALID_PARAMETER, string("Invalid parameter, duplicated txid: ")+txid.get_str());
+       setTxids.insert(hash);
+       oneTxid = hash;
+    }
+
+    LOCK(cs_main);
+
+    CBlockIndex* pblockindex = NULL;
+
+    uint256 hashBlock;
+    if (params.size() > 1)
+    {
+        hashBlock = uint256S(params[1].get_str());
+        if (!mapBlockIndex.count(hashBlock))
+            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
+        pblockindex = mapBlockIndex[hashBlock];
+    } else {
+        CCoins coins;
+        if (pcoinsTip->GetCoins(oneTxid, coins) && coins.nHeight > 0 && coins.nHeight <= chainActive.Height())
+            pblockindex = chainActive[coins.nHeight];
+    }
+
+    if (pblockindex == NULL)
+    {
+        CTransaction tx;
+        if (!GetTransaction(oneTxid, tx, hashBlock, false) || hashBlock.IsNull())
+            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Transaction not yet in block");
+        if (!mapBlockIndex.count(hashBlock))
+            throw JSONRPCError(RPC_INTERNAL_ERROR, "Transaction index corrupt");
+        pblockindex = mapBlockIndex[hashBlock];
+    }
+
+    CBlock block;
+    if(!ReadBlockFromDisk(block, pblockindex))
+        throw JSONRPCError(RPC_INTERNAL_ERROR, "Can't read block from disk");
+
+    unsigned int ntxFound = 0;
+    BOOST_FOREACH(const CTransaction&tx, block.vtx)
+        if (setTxids.count(tx.GetHash()))
+            ntxFound++;
+    if (ntxFound != setTxids.size())
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "(Not all) transactions not found in specified block");
+
+    CDataStream ssMB(SER_NETWORK, PROTOCOL_VERSION);
+    CMerkleBlock mb(block, setTxids);
+    ssMB << mb;
+    std::string strHex = HexStr(ssMB.begin(), ssMB.end());
+    return strHex;
+}
+
+Value verifytxoutproof(const Array& params, bool fHelp)
+{
+    if (fHelp || params.size() != 1)
+        throw runtime_error(
+            "verifytxoutproof \"proof\"\n"
+            "\nVerifies that a proof points to a transaction in a block, returning the transaction it commits to\n"
+            "and throwing an RPC error if the block is not in our best chain\n"
+            "\nArguments:\n"
+            "1. \"proof\"    (string, required) The hex-encoded proof generated by gettxoutproof\n"
+            "\nResult:\n"
+            "[\"txid\"]      (array, strings) The txid(s) which the proof commits to, or empty array if the proof is invalid\n"
+        );
+
+    CDataStream ssMB(ParseHexV(params[0], "proof"), SER_NETWORK, PROTOCOL_VERSION);
+    CMerkleBlock merkleBlock;
+    ssMB >> merkleBlock;
+
+    Array res;
+
+    vector<uint256> vMatch;
+    if (merkleBlock.txn.ExtractMatches(vMatch) != merkleBlock.header.hashMerkleRoot)
+        return res;
+
+    LOCK(cs_main);
+
+    if (!mapBlockIndex.count(merkleBlock.header.GetHash()) || !chainActive.Contains(mapBlockIndex[merkleBlock.header.GetHash()]))
+        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found in chain");
+
+    BOOST_FOREACH(const uint256& hash, vMatch)
+        res.push_back(hash.GetHex());
+    return res;
+}
+
 Value createrawtransaction(const Array& params, bool fHelp)
 {
     if (fHelp || params.size() != 2)

src/rpcserver.cpp

@@ -293,6 +293,8 @@ static const CRPCCommand vRPCCommands[] =
     { "blockchain",         "getmempoolinfo",         &getmempoolinfo,         true  },
     { "blockchain",         "getrawmempool",          &getrawmempool,          true  },
     { "blockchain",         "gettxout",               &gettxout,               true  },
+    { "blockchain",         "gettxoutproof",          &gettxoutproof,          true  },
+    { "blockchain",         "verifytxoutproof",       &verifytxoutproof,       true  },
     { "blockchain",         "gettxoutsetinfo",        &gettxoutsetinfo,        true  },
     { "blockchain",         "verifychain",            &verifychain,            true  },
 

src/rpcserver.h

@@ -218,6 +218,8 @@ extern json_spirit::Value decoderawtransaction(const json_spirit::Array& params,
 extern json_spirit::Value decodescript(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value signrawtransaction(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value sendrawtransaction(const json_spirit::Array& params, bool fHelp);
+extern json_spirit::Value gettxoutproof(const json_spirit::Array& params, bool fHelp);
+extern json_spirit::Value verifytxoutproof(const json_spirit::Array& params, bool fHelp);
 
 extern json_spirit::Value getblockcount(const json_spirit::Array& params, bool fHelp); // in rpcblockchain.cpp
 extern json_spirit::Value getbestblockhash(const json_spirit::Array& params, bool fHelp);