Skip to content

Commit

Permalink
Pick rounds with the most inputs available to mix first (dashpay#2278)
Browse files Browse the repository at this point in the history 
* Alternative solution: pick rounds with the most inputs available to mix first

* randomly skip some inputs when we have at least one of this denom already

* More randomization in PrepareDenominate

* fix `vecSteps[nBit] >= 1 ?` and adjust speed/privacy ratio for more speed i.e. `GetRandInt(5) == 0`

* fix typos

* no comments
  • Loading branch information
@UdjinM6 @CryptoCentric
UdjinM6 authored and CryptoCentric committed May 20, 2019
1 parent cb0fb92 commit 446e254
Show file tree
Hide file tree
Showing 2 changed files with 45 additions and 37 deletions.
80 changes: 44 additions & 36 deletions src/privatesend-client.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1168,17 +1168,6 @@ void CPrivateSendClientManager::ProcessPendingDsaRequest(CConnman& connman)

bool CPrivateSendClientSession::SubmitDenominate(CConnman& connman)
{
// This is just a local helper
auto GetStartRound = [](bool fMixLowest, bool fScanFromTheMiddle) -> int
{
if (fScanFromTheMiddle) {
return privateSendClient.nPrivateSendRounds / 2;
} else if (!fMixLowest) {
return privateSendClient.nPrivateSendRounds - 1;
}
return 0;
};

LOCK2(cs_main, pwalletMain->cs_wallet);

std::string strError;
Expand All @@ -1189,28 +1178,36 @@ bool CPrivateSendClientSession::SubmitDenominate(CConnman& connman)
return false;
}

// lean towards "highest" branch but still mix via "lowest" one someties
bool fMixLowest = privateSendClient.nLiquidityProvider || (GetRandInt(4) == 0);
// Try to use only inputs with the same number of rounds, from low to high, or vice versa
int nLoopStep = fMixLowest ? 1 : -1;
// lean towards edges but still mix starting from the middle someties
// Note: liqudity providers always start from 0
bool fScanFromTheMiddle = (privateSendClient.nLiquidityProvider == 0) && (GetRandInt(4) == 0);

int nRoundStart = GetStartRound(fMixLowest, fScanFromTheMiddle);
int nRoundEdge = GetStartRound(fMixLowest, false);
std::vector< std::pair<int, size_t> > vecInputsByRounds;
// Note: liquidity providers are fine with whatever number of inputs they've got
bool fDryRun = privateSendClient.nLiquidityProvider == 0;

// Submit transaction to the pool if we get here
while (true) {
for (int i = nRoundStart; i >= 0 && i < privateSendClient.nPrivateSendRounds; i += nLoopStep) {
if (PrepareDenominate(i, i, strError, vecPSInOutPairs, vecPSInOutPairsTmp)) {
LogPrintf("CPrivateSendClientSession::SubmitDenominate -- Running PrivateSend denominate for %d rounds, success\n", i);
for (int i = 0; i < privateSendClient.nPrivateSendRounds; i++) {
if (PrepareDenominate(i, i, strError, vecPSInOutPairs, vecPSInOutPairsTmp, fDryRun)) {
LogPrintf("CPrivateSendClientSession::SubmitDenominate -- Running PrivateSend denominate for %d rounds, success\n", i);
if (!fDryRun) {
return SendDenominate(vecPSInOutPairsTmp, connman);
}
vecInputsByRounds.emplace_back(i, vecPSInOutPairsTmp.size());
} else {
LogPrint("privatesend", "CPrivateSendClientSession::SubmitDenominate -- Running PrivateSend denominate for %d rounds, error: %s\n", i, strError);
}
if (nRoundStart == nRoundEdge) break;
nRoundStart = nRoundEdge;
}

// more inputs first, for equal input count prefer the one with less rounds
std::sort(vecInputsByRounds.begin(), vecInputsByRounds.end(), [](const auto& a, const auto& b) {
return a.second > b.second || (a.second == b.second && a.first < b.first);
});

LogPrint("privatesend", "vecInputsByRounds for denom %d\n", nSessionDenom);
for (const auto& pair : vecInputsByRounds) {
LogPrint("privatesend", "vecInputsByRounds: rounds: %d, inputs: %d\n", pair.first, pair.second);
}

int nRounds = vecInputsByRounds.begin()->first;
if (PrepareDenominate(nRounds, nRounds, strError, vecPSInOutPairs, vecPSInOutPairsTmp)) {
LogPrintf("CPrivateSendClientSession::SubmitDenominate -- Running PrivateSend denominate for %d rounds, success\n", nRounds);
return SendDenominate(vecPSInOutPairsTmp, connman);
}

// We failed? That's strange but let's just make final attempt and try to mix everything
Expand Down Expand Up @@ -1260,7 +1257,7 @@ bool CPrivateSendClientSession::SelectDenominate(std::string& strErrorRet, std::
return true;
}

bool CPrivateSendClientSession::PrepareDenominate(int nMinRounds, int nMaxRounds, std::string& strErrorRet, const std::vector< std::pair<CTxDSIn, CTxOut> >& vecPSInOutPairsIn, std::vector< std::pair<CTxDSIn, CTxOut> >& vecPSInOutPairsRet)
bool CPrivateSendClientSession::PrepareDenominate(int nMinRounds, int nMaxRounds, std::string& strErrorRet, const std::vector< std::pair<CTxDSIn, CTxOut> >& vecPSInOutPairsIn, std::vector< std::pair<CTxDSIn, CTxOut> >& vecPSInOutPairsRet, bool fDryRun)
{
std::vector<int> vecBits;
if (!CPrivateSend::GetDenominationsBits(nSessionDenom, vecBits)) {
Expand All @@ -1272,16 +1269,15 @@ bool CPrivateSendClientSession::PrepareDenominate(int nMinRounds, int nMaxRounds
pwalletMain->LockCoin(pair.first.prevout);
}

// Try to add every needed denomination, repeat up to 5-PRIVATESEND_ENTRY_MAX_SIZE times.
// NOTE: No need to randomize order of inputs because they were
// initially shuffled in CWallet::SelectPSInOutPairsByDenominations already.
int nStepsMax = 5 + GetRandInt(PRIVATESEND_ENTRY_MAX_SIZE - 5 + 1);
int nDenomResult{0};

std::vector<CAmount> vecStandardDenoms = CPrivateSend::GetStandardDenominations();
std::vector<int> vecSteps(vecStandardDenoms.size(), 0);
vecPSInOutPairsRet.clear();

// Try to add up to PRIVATESEND_ENTRY_MAX_SIZE of every needed denomination
for (const auto& pair: vecPSInOutPairsIn) {
if (pair.second.nRounds < nMinRounds || pair.second.nRounds > nMaxRounds) {
// unlock unused coins
Expand All @@ -1290,10 +1286,23 @@ bool CPrivateSendClientSession::PrepareDenominate(int nMinRounds, int nMaxRounds
}
bool fFound = false;
for (const auto& nBit : vecBits) {
if (vecSteps[nBit] >= nStepsMax) break;
if (vecSteps[nBit] >= PRIVATESEND_ENTRY_MAX_SIZE) break;
CAmount nValueDenom = vecStandardDenoms[nBit];
if (pair.second.nValue == nValueDenom) {
CScript scriptDenom = keyHolderStorage.AddKey(pwalletMain);
CScript scriptDenom;
if (fDryRun) {
scriptDenom = CScript();
} else {
// randomly skip some inputs when we have at least one of the same denom already
// TODO: make it adjustable via options/cmd-line params
if (vecSteps[nBit] >= 1 && GetRandInt(5) == 0) {
// still count it as a step to randomize number of inputs
// if we have more than (or exactly) PRIVATESEND_ENTRY_MAX_SIZE of them
++vecSteps[nBit];
break;
}
scriptDenom = keyHolderStorage.AddKey(pwalletMain);
}
vecPSInOutPairsRet.emplace_back(pair.first, CTxOut(nValueDenom, scriptDenom));
fFound = true;
nDenomResult |= 1 << nBit;
Expand All @@ -1302,8 +1311,8 @@ bool CPrivateSendClientSession::PrepareDenominate(int nMinRounds, int nMaxRounds
break;
}
}
if (!fFound) {
// unlock unused coins
if (!fFound || fDryRun) {
// unlock unused coins and if we are not going to mix right away
pwalletMain->UnlockCoin(pair.first.prevout);
}
}
Expand All @@ -1318,7 +1327,6 @@ bool CPrivateSendClientSession::PrepareDenominate(int nMinRounds, int nMaxRounds
return false;
}

// We also do not care about full amount as long as we have right denominations
return true;
}

Expand Down
2 changes: 1 addition & 1 deletion src/privatesend-client.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -111,7 +111,7 @@ class CPrivateSendClientSession : public CPrivateSendBaseSession
/// step 0: select denominated inputs and txouts
bool SelectDenominate(std::string& strErrorRet, std::vector< std::pair<CTxDSIn, CTxOut> >& vecPSInOutPairsRet);
/// step 1: prepare denominated inputs and outputs
bool PrepareDenominate(int nMinRounds, int nMaxRounds, std::string& strErrorRet, const std::vector< std::pair<CTxDSIn, CTxOut> >& vecPSInOutPairsIn, std::vector< std::pair<CTxDSIn, CTxOut> >& vecPSInOutPairsRet);
bool PrepareDenominate(int nMinRounds, int nMaxRounds, std::string& strErrorRet, const std::vector< std::pair<CTxDSIn, CTxOut> >& vecPSInOutPairsIn, std::vector< std::pair<CTxDSIn, CTxOut> >& vecPSInOutPairsRet, bool fDryRun = false);
/// step 2: send denominated inputs and outputs prepared in step 1
bool SendDenominate(const std::vector< std::pair<CTxDSIn, CTxOut> >& vecPSInOutPairsIn, CConnman& connman);

Expand Down

0 comments on commit 446e254

Please sign in to comment.