Method CreateCollateralTransaction

src/wallet.cpp:2684–2742

}

bool CWallet::CreateCollateralTransaction(CMutableTransaction& txCollateral, std::string& strReason)
{
    /*
        To doublespend a collateral transaction, it will require a fee higher than this. So there's
        still a significant cost.
    */
    CAmount nFeeRet = 1 * COIN;

    txCollateral.vin.clear();
    txCollateral.vout.clear();

    CReserveKey reservekey(this);
    CAmount nValueIn2 = 0;
    std::vector<CTxIn> vCoinsCollateral;

    if (!SelectCoinsCollateral(vCoinsCollateral, nValueIn2)) {
        strReason = "Error: DarkSend requires a collateral transaction and could not locate an acceptable input!";
        return false;
    }

    // make our change address
    CScript scriptChange;
    CPubKey vchPubKey;
    bool success = reservekey.GetReservedKey(vchPubKey, true);
    assert(success); // should never fail, as we just unlocked
    scriptChange = GetScriptForDestination(vchPubKey.GetID());
    reservekey.KeepKey();

    for (CTxIn v : vCoinsCollateral)
        txCollateral.vin.push_back(v);

    if (nValueIn2 - DARKSEND_COLLATERAL - nFeeRet > 0) {
        //pay collateral charge in fees
        CTxOut vout3 = CTxOut(nValueIn2 - DARKSEND_COLLATERAL, scriptChange);
        txCollateral.vout.push_back(vout3);
    }

    int vinNumber = 0;
    for (CTxIn v : txCollateral.vin) {
        CTransaction txPrev;
        uint256 prevBlockHash;
        //Find previous transaction with the same output as txNew input
        if (!GetTransaction(v.prevout.hash, txPrev, Params().GetConsensus(), prevBlockHash)) {
            strReason = "CDarkSendPool::MutateTxSign() - Signing - Failed to get previous transaction\n";
            return false;
        }
        const CAmount& amount = txPrev.vout[v.prevout.n].nValue;
        if (!SignSignature(*this, v.prevPubKey, txCollateral, vinNumber, amount, int(SIGHASH_ALL | SIGHASH_ANYONECANPAY))) {
            for (CTxIn v : vCoinsCollateral)
                UnlockCoin(v.prevout);

            strReason = "CDarkSendPool::Sign - Unable to sign collateral transaction! \n";
            return false;
        }
        vinNumber++;
    }

    return true;