Merge ElementsProject#636: have peg-in witness creation strip witness…

… for space savings

7737d29 have peg-in witness creation strip witness for space savings (Gregory Sanders)

Pull request description:

  Cheaper peg-in witness for those with segwit transactions in Bitcoin.

  resolves ElementsProject#628

Tree-SHA512: defc4f38b2456c6f45cf2ebd48a3d5f9e39544bd048606257ef6cf90623595c159f61e3df56845fb7a37a44b5019614e692663978a9664dd9b4d01b77bedeb86

src/wallet/rpcwallet.cpp

@@ -5417,14 +5417,19 @@ static UniValue createrawpegin(const JSONRPCRequest& request, T_tx_ref& txBTCRef
     mtx.vout.push_back(CTxOut(Params().GetConsensus().pegged_asset, value, GetScriptForDestination(wpkhash)));
     mtx.vout.push_back(CTxOut(Params().GetConsensus().pegged_asset, 0, CScript()));
 
+    // Strip witness data for proof inclusion since only TXID-covered fields matters
+    CDataStream ssTxBack(SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS);
+    ssTxBack << txBTC;
+    std::vector<unsigned char> tx_data_stripped(ssTxBack.begin(), ssTxBack.end());
+
     // Construct pegin proof
     CScriptWitness pegin_witness;
     std::vector<std::vector<unsigned char> >& stack = pegin_witness.stack;
     stack.push_back(value_bytes);
     stack.push_back(std::vector<unsigned char>(Params().GetConsensus().pegged_asset.begin(), Params().GetConsensus().pegged_asset.end()));
     stack.push_back(std::vector<unsigned char>(genesisBlockHash.begin(), genesisBlockHash.end()));
     stack.push_back(std::vector<unsigned char>(witness_script.begin(), witness_script.end()));
-    stack.push_back(txData);
+    stack.push_back(tx_data_stripped);
     stack.push_back(txOutProofData);
 
     // Peg-in witness isn't valid, even though the block header is(without depth check)