public static string SignTx(string TxJSON, string extPrivateKey, bool testnet)
{
try
{
Network ntwk = testnet ? Network.TestNet : Network.Main;
TxSerial txs = Newtonsoft.Json.JsonConvert.DeserializeObject <TxSerial>(TxJSON);
ExtKey p2 = ExtKey.Parse(extPrivateKey);
ExtKey RootKey = p2;
TransactionBuilder bldr = new TransactionBuilder();
bldr.Send(new BitcoinPubKeyAddress(txs.ToAddress), Money.Satoshis(txs.SendAmt));
bldr.SetChange(new BitcoinPubKeyAddress(txs.ChgAddress));
bldr.SendFees(Money.Satoshis(txs.Fee));
//re-add coins
List <Coin> lstCoin = new List <Coin>();
foreach (UTXO u in txs.InputUTXOs)
{
Coin cn;
bldr.AddCoins(cn = new Coin(
new OutPoint(new uint256(u.Tx_hash), u.Tx_pos), //tx that funded wallet, spend this coin
new TxOut(Money.Satoshis(u.Value), new BitcoinPubKeyAddress(u.Address))));
lstCoin.Add(cn);
}
Transaction tx = bldr.BuildTransaction(false); //will select coins
foreach (UTXO u in txs.InputUTXOs)
{
Coin cn;
bldr.AddCoins(cn = new Coin(
new OutPoint(new uint256(u.Tx_hash), u.Tx_pos), //tx that funded wallet, spend this coin
new TxOut(Money.Satoshis(u.Value), new BitcoinPubKeyAddress(u.Address))));
//check if coin in spend list, else error (should already be done in CreateTx)
foreach (TxIn i in tx.Inputs)
{
if (i.PrevOut == cn.Outpoint) //this coin is in tx
//sign utxo with corresponding private key
{
bldr.AddKnownSignature(new PubKey(u.PublicKey), tx.SignInput(new BitcoinSecret(RootKey.Derive((uint)u.AddrType).Derive(u.AddrIndex).PrivateKey, ntwk), cn));
}
}
}
Transaction txSigned = bldr.BuildTransaction(true);
NBitcoin.Policy.TransactionPolicyError[] pe;
bool verify = bldr.Verify(txSigned, out pe);
string hx = txSigned.ToHex();
return(hx);
}
catch (Exception ex)
{
string result = "ERROR: " + ex.Message;
return(result);
}
}
//take in tx parameters, return tx object
public static TxSerial CreateTx(string extPubKey, string pubToAddr, string chgAddr, int walletId, long satToSend, long fee, bool testnet)
{
CheckNullOrEmpty(new object[] { extPubKey, pubToAddr, ElectrumXhost },
new string[] { "extPubKey", "pubToAddr", "ElectrumXhost" });
string err = "";
if (satToSend == 0)
{
err += "satoshiToSend = 0, ";
}
if (fee == 0)
{
err += "satoshiFee = 0, ";
}
if (err != "")
{
throw new Exception("[CreateTx] " + err);
}
//get first 100+100 child address from ext pub key
List <Tuple <string, string> > recAddrList = GetDerivedKeys(extPubKey, 0, 20, false, testnet); //receive addresses
List <Tuple <string, string> > chgAddrList = GetDerivedKeys(extPubKey, 0, 20, true, testnet); //change addresses
//TODO - create process for getting next change address, so address never used twice
if (chgAddr == null || chgAddr == "") //get first chg addr for extPubKey
{
chgAddr = chgAddrList.First().Item1;
}
//server status check
string info = ElectrumX.GetServerInfo(ElectrumXhost, ElectrumXport);
if (info == null)
{
throw new Exception("[CreateTx] ElectrumX Server Check Failed");
}
string[] recAddrListAddr = new string[recAddrList.Count]; //short address
string[] recAddrListExt = new string[recAddrList.Count]; //long address
int ctr = 0;
foreach (var t in recAddrList)
{
recAddrListAddr[ctr++] = t.Item1; //short
}
ctr = 0;
foreach (var t in recAddrList)
{
recAddrListExt[ctr++] = t.Item2; //long - hash
}
string[] chgAddrListAddr = new string[recAddrList.Count];
string[] chgAddrListExt = new string[recAddrList.Count];
ctr = 0;
foreach (var t in chgAddrList)
{
chgAddrListAddr[ctr++] = t.Item1;
}
ctr = 0;
foreach (var t in chgAddrList)
{
chgAddrListExt[ctr++] = t.Item2;
}
//get all UTXOs (unspent inputs) from receive addresses
UTXO[] recUTXOs = ElectrumX.GetUTXOs(recAddrList, ElectrumXhost, ElectrumXport);
UTXO.SetAddressType(recUTXOs, 0); //receiver
//get all UTXOs (unspent inputs) from change addresses
UTXO[] chgUTXOs = ElectrumX.GetUTXOs(chgAddrList, ElectrumXhost, ElectrumXport);
UTXO.SetAddressType(chgUTXOs, 1); //change
//start new tx
TransactionBuilder bldr = new TransactionBuilder();
bldr.Send(new BitcoinPubKeyAddress(pubToAddr), Money.Satoshis(satToSend)); //amount to send to recipient
bldr.SetChange(new BitcoinPubKeyAddress(chgAddr)); //send change to this address
bldr.SendFees(Money.Satoshis(fee)); //miner (tx) fee
//collect all UTXOs
List <UTXO> allUTXOs = new List <UTXO>();
allUTXOs.AddRange(recUTXOs);
allUTXOs.AddRange(chgUTXOs);
List <ICoin> lstTxCoins = new List <ICoin>(); //Coin is a UTXO
//add new coin for each UTXO
foreach (UTXO x in allUTXOs) //tx builder will select coins from this list
{
BitcoinPubKeyAddress fromAddr = new BitcoinPubKeyAddress(x.Address);
NBitcoin.Coin cn = null;
//create new coin from UTXO
bldr.AddCoins(cn = new NBitcoin.Coin(
new OutPoint(new uint256(x.Tx_hash), x.Tx_pos), //tx that funded wallet, spend this coin
new TxOut(Money.Satoshis(x.Value), fromAddr.ScriptPubKey))); //specify full coin amount, else SetChange ignored
lstTxCoins.Add(cn); //add coin to transaction, may not be used
x.tmp = cn; //link UTXO with coin
}
List <UTXO> usedUTXOs = new List <UTXO>(); //coins actually used in tx
NBitcoin.Transaction tx = bldr.BuildTransaction(false); //sort\filter coins, some coins will not be needed\used
//coin objects not stored in tx, so we need to determine which coins were used
//scan tx inputs for matching coins, ignore other coins
foreach (UTXO u in allUTXOs)
{
foreach (TxIn i in tx.Inputs)
{
if (i.PrevOut == ((NBitcoin.Coin)u.tmp).Outpoint) //this coin in tx
{
usedUTXOs.Add(u); //this UTXO will be used\spent in tx
}
}
}
//populate return object
TxSerial txs = new TxSerial()
{
SendAmt = satToSend,
Fee = fee,
ExtPublicKey = extPubKey,
ToAddress = pubToAddr,
ChgAddress = chgAddr,
WalletId = walletId
};
txs.ExtPublicKey = extPubKey;
foreach (UTXO u in usedUTXOs)
{
u.tmp = null; //don't serialize coin object, will rebuild coins in signing process
}
txs.InputUTXOs = new List <UTXO>();
txs.InputUTXOs.AddRange(usedUTXOs);
//string jsn = Newtonsoft.Json.JsonConvert.SerializeObject(txs, Newtonsoft.Json.Formatting.Indented);
return(txs);
}
public static string CreateTxJSON(string extPubKey, string pubToAddr, string chgAddr, int walletId, long satToSend, long fee, bool testnet)
{
TxSerial ts = CreateTx(extPubKey, pubToAddr, chgAddr, walletId, satToSend, fee, testnet);
return(Newtonsoft.Json.JsonConvert.SerializeObject(ts, Newtonsoft.Json.Formatting.Indented));
}
