Merge #8524: Precompute sighashes

35fe039 Rename to PrecomputedTransactionData (Pieter Wuille)
ab48c5e Unit test for sighash caching (Nicolas DORIER)
d2c5d04 Precompute sighashes (Pieter Wuille)
This commit is contained in:
Pieter Wuille 2016-09-01 12:09:36 +02:00
commit 19b0f33de0
No known key found for this signature in database
GPG Key ID: DBA1A67379A1A931
8 changed files with 159 additions and 38 deletions

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@ -1496,12 +1496,13 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
// Check against previous transactions
// This is done last to help prevent CPU exhaustion denial-of-service attacks.
if (!CheckInputs(tx, state, view, true, scriptVerifyFlags, true)) {
PrecomputedTransactionData txdata(tx);
if (!CheckInputs(tx, state, view, true, scriptVerifyFlags, true, txdata)) {
// SCRIPT_VERIFY_CLEANSTACK requires SCRIPT_VERIFY_WITNESS, so we
// need to turn both off, and compare against just turning off CLEANSTACK
// to see if the failure is specifically due to witness validation.
if (CheckInputs(tx, state, view, true, scriptVerifyFlags & ~(SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_CLEANSTACK), true) &&
!CheckInputs(tx, state, view, true, scriptVerifyFlags & ~SCRIPT_VERIFY_CLEANSTACK, true)) {
if (CheckInputs(tx, state, view, true, scriptVerifyFlags & ~(SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_CLEANSTACK), true, txdata) &&
!CheckInputs(tx, state, view, true, scriptVerifyFlags & ~SCRIPT_VERIFY_CLEANSTACK, true, txdata)) {
// Only the witness is wrong, so the transaction itself may be fine.
state.SetCorruptionPossible();
}
@ -1517,7 +1518,7 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
// There is a similar check in CreateNewBlock() to prevent creating
// invalid blocks, however allowing such transactions into the mempool
// can be exploited as a DoS attack.
if (!CheckInputs(tx, state, view, true, MANDATORY_SCRIPT_VERIFY_FLAGS, true))
if (!CheckInputs(tx, state, view, true, MANDATORY_SCRIPT_VERIFY_FLAGS, true, txdata))
{
return error("%s: BUG! PLEASE REPORT THIS! ConnectInputs failed against MANDATORY but not STANDARD flags %s, %s",
__func__, hash.ToString(), FormatStateMessage(state));
@ -1914,7 +1915,7 @@ void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, int nHeight)
bool CScriptCheck::operator()() {
const CScript &scriptSig = ptxTo->vin[nIn].scriptSig;
const CScriptWitness *witness = (nIn < ptxTo->wit.vtxinwit.size()) ? &ptxTo->wit.vtxinwit[nIn].scriptWitness : NULL;
if (!VerifyScript(scriptSig, scriptPubKey, witness, nFlags, CachingTransactionSignatureChecker(ptxTo, nIn, amount, cacheStore), &error)) {
if (!VerifyScript(scriptSig, scriptPubKey, witness, nFlags, CachingTransactionSignatureChecker(ptxTo, nIn, amount, cacheStore, *txdata), &error)) {
return false;
}
return true;
@ -1973,7 +1974,7 @@ bool CheckTxInputs(const CTransaction& tx, CValidationState& state, const CCoins
}
}// namespace Consensus
bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheStore, std::vector<CScriptCheck> *pvChecks)
bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheStore, PrecomputedTransactionData& txdata, std::vector<CScriptCheck> *pvChecks)
{
if (!tx.IsCoinBase())
{
@ -2000,7 +2001,7 @@ bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsVi
assert(coins);
// Verify signature
CScriptCheck check(*coins, tx, i, flags, cacheStore);
CScriptCheck check(*coins, tx, i, flags, cacheStore, &txdata);
if (pvChecks) {
pvChecks->push_back(CScriptCheck());
check.swap(pvChecks->back());
@ -2013,7 +2014,7 @@ bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsVi
// avoid splitting the network between upgraded and
// non-upgraded nodes.
CScriptCheck check2(*coins, tx, i,
flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, cacheStore);
flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, cacheStore, &txdata);
if (check2())
return state.Invalid(false, REJECT_NONSTANDARD, strprintf("non-mandatory-script-verify-flag (%s)", ScriptErrorString(check.GetScriptError())));
}
@ -2409,6 +2410,8 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
std::vector<std::pair<uint256, CDiskTxPos> > vPos;
vPos.reserve(block.vtx.size());
blockundo.vtxundo.reserve(block.vtx.size() - 1);
std::vector<PrecomputedTransactionData> txdata;
txdata.reserve(block.vtx.size()); // Required so that pointers to individual PrecomputedTransactionData don't get invalidated
for (unsigned int i = 0; i < block.vtx.size(); i++)
{
const CTransaction &tx = block.vtx[i];
@ -2455,13 +2458,14 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
return state.DoS(100, error("ConnectBlock(): too many sigops"),
REJECT_INVALID, "bad-blk-sigops");
txdata.emplace_back(tx);
if (!tx.IsCoinBase())
{
nFees += view.GetValueIn(tx)-tx.GetValueOut();
std::vector<CScriptCheck> vChecks;
bool fCacheResults = fJustCheck; /* Don't cache results if we're actually connecting blocks (still consult the cache, though) */
if (!CheckInputs(tx, state, view, fScriptChecks, flags, fCacheResults, nScriptCheckThreads ? &vChecks : NULL))
if (!CheckInputs(tx, state, view, fScriptChecks, flags, fCacheResults, txdata[i], nScriptCheckThreads ? &vChecks : NULL))
return error("ConnectBlock(): CheckInputs on %s failed with %s",
tx.GetHash().ToString(), FormatStateMessage(state));
control.Add(vChecks);

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@ -38,6 +38,7 @@ class CScriptCheck;
class CTxMemPool;
class CValidationInterface;
class CValidationState;
class PrecomputedTransactionData;
struct CNodeStateStats;
struct LockPoints;
@ -347,7 +348,7 @@ int64_t GetTransactionSigOpCost(const CTransaction& tx, const CCoinsViewCache& i
* instead of being performed inline.
*/
bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &view, bool fScriptChecks,
unsigned int flags, bool cacheStore, std::vector<CScriptCheck> *pvChecks = NULL);
unsigned int flags, bool cacheStore, PrecomputedTransactionData& txdata, std::vector<CScriptCheck> *pvChecks = NULL);
/** Apply the effects of this transaction on the UTXO set represented by view */
void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, int nHeight);
@ -421,12 +422,13 @@ private:
unsigned int nFlags;
bool cacheStore;
ScriptError error;
PrecomputedTransactionData *txdata;
public:
CScriptCheck(): amount(0), ptxTo(0), nIn(0), nFlags(0), cacheStore(false), error(SCRIPT_ERR_UNKNOWN_ERROR) {}
CScriptCheck(const CCoins& txFromIn, const CTransaction& txToIn, unsigned int nInIn, unsigned int nFlagsIn, bool cacheIn) :
CScriptCheck(const CCoins& txFromIn, const CTransaction& txToIn, unsigned int nInIn, unsigned int nFlagsIn, bool cacheIn, PrecomputedTransactionData* txdataIn) :
scriptPubKey(txFromIn.vout[txToIn.vin[nInIn].prevout.n].scriptPubKey), amount(txFromIn.vout[txToIn.vin[nInIn].prevout.n].nValue),
ptxTo(&txToIn), nIn(nInIn), nFlags(nFlagsIn), cacheStore(cacheIn), error(SCRIPT_ERR_UNKNOWN_ERROR) { }
ptxTo(&txToIn), nIn(nInIn), nFlags(nFlagsIn), cacheStore(cacheIn), error(SCRIPT_ERR_UNKNOWN_ERROR), txdata(txdataIn) { }
bool operator()();
@ -438,6 +440,7 @@ public:
std::swap(nFlags, check.nFlags);
std::swap(cacheStore, check.cacheStore);
std::swap(error, check.error);
std::swap(txdata, check.txdata);
}
ScriptError GetScriptError() const { return error; }

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@ -84,8 +84,8 @@ static int verify_script(const unsigned char *scriptPubKey, unsigned int scriptP
// Regardless of the verification result, the tx did not error.
set_error(err, bitcoinconsensus_ERR_OK);
return VerifyScript(tx.vin[nIn].scriptSig, CScript(scriptPubKey, scriptPubKey + scriptPubKeyLen), nIn < tx.wit.vtxinwit.size() ? &tx.wit.vtxinwit[nIn].scriptWitness : NULL, flags, TransactionSignatureChecker(&tx, nIn, amount), NULL);
PrecomputedTransactionData txdata(tx);
return VerifyScript(tx.vin[nIn].scriptSig, CScript(scriptPubKey, scriptPubKey + scriptPubKeyLen), nIn < tx.wit.vtxinwit.size() ? &tx.wit.vtxinwit[nIn].scriptWitness : NULL, flags, TransactionSignatureChecker(&tx, nIn, amount, txdata), NULL);
} catch (const std::exception&) {
return set_error(err, bitcoinconsensus_ERR_TX_DESERIALIZE); // Error deserializing
}

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@ -1108,9 +1108,40 @@ public:
}
};
uint256 GetPrevoutHash(const CTransaction& txTo) {
CHashWriter ss(SER_GETHASH, 0);
for (unsigned int n = 0; n < txTo.vin.size(); n++) {
ss << txTo.vin[n].prevout;
}
return ss.GetHash();
}
uint256 GetSequenceHash(const CTransaction& txTo) {
CHashWriter ss(SER_GETHASH, 0);
for (unsigned int n = 0; n < txTo.vin.size(); n++) {
ss << txTo.vin[n].nSequence;
}
return ss.GetHash();
}
uint256 GetOutputsHash(const CTransaction& txTo) {
CHashWriter ss(SER_GETHASH, 0);
for (unsigned int n = 0; n < txTo.vout.size(); n++) {
ss << txTo.vout[n];
}
return ss.GetHash();
}
} // anon namespace
uint256 SignatureHash(const CScript& scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType, const CAmount& amount, SigVersion sigversion)
PrecomputedTransactionData::PrecomputedTransactionData(const CTransaction& txTo)
{
hashPrevouts = GetPrevoutHash(txTo);
hashSequence = GetSequenceHash(txTo);
hashOutputs = GetOutputsHash(txTo);
}
uint256 SignatureHash(const CScript& scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType, const CAmount& amount, SigVersion sigversion, const PrecomputedTransactionData* cache)
{
if (sigversion == SIGVERSION_WITNESS_V0) {
uint256 hashPrevouts;
@ -1118,27 +1149,16 @@ uint256 SignatureHash(const CScript& scriptCode, const CTransaction& txTo, unsig
uint256 hashOutputs;
if (!(nHashType & SIGHASH_ANYONECANPAY)) {
CHashWriter ss(SER_GETHASH, 0);
for (unsigned int n = 0; n < txTo.vin.size(); n++) {
ss << txTo.vin[n].prevout;
}
hashPrevouts = ss.GetHash(); // TODO: cache this value for all signatures in a transaction
hashPrevouts = cache ? cache->hashPrevouts : GetPrevoutHash(txTo);
}
if (!(nHashType & SIGHASH_ANYONECANPAY) && (nHashType & 0x1f) != SIGHASH_SINGLE && (nHashType & 0x1f) != SIGHASH_NONE) {
CHashWriter ss(SER_GETHASH, 0);
for (unsigned int n = 0; n < txTo.vin.size(); n++) {
ss << txTo.vin[n].nSequence;
}
hashSequence = ss.GetHash(); // TODO: cache this value for all signatures in a transaction
hashSequence = cache ? cache->hashSequence : GetSequenceHash(txTo);
}
if ((nHashType & 0x1f) != SIGHASH_SINGLE && (nHashType & 0x1f) != SIGHASH_NONE) {
CHashWriter ss(SER_GETHASH, 0);
for (unsigned int n = 0; n < txTo.vout.size(); n++) {
ss << txTo.vout[n];
}
hashOutputs = ss.GetHash(); // TODO: cache this value for all signatures in a transaction
hashOutputs = cache ? cache->hashOutputs : GetOutputsHash(txTo);
} else if ((nHashType & 0x1f) == SIGHASH_SINGLE && nIn < txTo.vout.size()) {
CHashWriter ss(SER_GETHASH, 0);
ss << txTo.vout[nIn];
@ -1209,7 +1229,7 @@ bool TransactionSignatureChecker::CheckSig(const vector<unsigned char>& vchSigIn
int nHashType = vchSig.back();
vchSig.pop_back();
uint256 sighash = SignatureHash(scriptCode, *txTo, nIn, nHashType, amount, sigversion);
uint256 sighash = SignatureHash(scriptCode, *txTo, nIn, nHashType, amount, sigversion, this->txdata);
if (!VerifySignature(vchSig, pubkey, sighash))
return false;

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@ -98,13 +98,20 @@ enum
bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, unsigned int flags, ScriptError* serror);
struct PrecomputedTransactionData
{
uint256 hashPrevouts, hashSequence, hashOutputs;
PrecomputedTransactionData(const CTransaction& tx);
};
enum SigVersion
{
SIGVERSION_BASE = 0,
SIGVERSION_WITNESS_V0 = 1,
};
uint256 SignatureHash(const CScript &scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType, const CAmount& amount, SigVersion sigversion);
uint256 SignatureHash(const CScript &scriptCode, const CTransaction& txTo, unsigned int nIn, int nHashType, const CAmount& amount, SigVersion sigversion, const PrecomputedTransactionData* cache = NULL);
class BaseSignatureChecker
{
@ -133,12 +140,14 @@ private:
const CTransaction* txTo;
unsigned int nIn;
const CAmount amount;
const PrecomputedTransactionData* txdata;
protected:
virtual bool VerifySignature(const std::vector<unsigned char>& vchSig, const CPubKey& vchPubKey, const uint256& sighash) const;
public:
TransactionSignatureChecker(const CTransaction* txToIn, unsigned int nInIn, const CAmount& amountIn) : txTo(txToIn), nIn(nInIn), amount(amountIn) {}
TransactionSignatureChecker(const CTransaction* txToIn, unsigned int nInIn, const CAmount& amountIn) : txTo(txToIn), nIn(nInIn), amount(amountIn), txdata(NULL) {}
TransactionSignatureChecker(const CTransaction* txToIn, unsigned int nInIn, const CAmount& amountIn, const PrecomputedTransactionData& txdataIn) : txTo(txToIn), nIn(nInIn), amount(amountIn), txdata(&txdataIn) {}
bool CheckSig(const std::vector<unsigned char>& scriptSig, const std::vector<unsigned char>& vchPubKey, const CScript& scriptCode, SigVersion sigversion) const;
bool CheckLockTime(const CScriptNum& nLockTime) const;
bool CheckSequence(const CScriptNum& nSequence) const;

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@ -22,7 +22,7 @@ private:
bool store;
public:
CachingTransactionSignatureChecker(const CTransaction* txToIn, unsigned int nInIn, const CAmount& amount, bool storeIn) : TransactionSignatureChecker(txToIn, nInIn, amount), store(storeIn) {}
CachingTransactionSignatureChecker(const CTransaction* txToIn, unsigned int nInIn, const CAmount& amount, bool storeIn, PrecomputedTransactionData& txdataIn) : TransactionSignatureChecker(txToIn, nInIn, amount, txdataIn), store(storeIn) {}
bool VerifySignature(const std::vector<unsigned char>& vchSig, const CPubKey& vchPubKey, const uint256& sighash) const;
};

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@ -107,12 +107,13 @@ BOOST_AUTO_TEST_CASE(sign)
}
// All of the above should be OK, and the txTos have valid signatures
// Check to make sure signature verification fails if we use the wrong ScriptSig:
for (int i = 0; i < 8; i++)
for (int i = 0; i < 8; i++) {
PrecomputedTransactionData txdata(txTo[i]);
for (int j = 0; j < 8; j++)
{
CScript sigSave = txTo[i].vin[0].scriptSig;
txTo[i].vin[0].scriptSig = txTo[j].vin[0].scriptSig;
bool sigOK = CScriptCheck(CCoins(txFrom, 0), txTo[i], 0, SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_STRICTENC, false)();
bool sigOK = CScriptCheck(CCoins(txFrom, 0), txTo[i], 0, SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_STRICTENC, false, &txdata)();
if (i == j)
BOOST_CHECK_MESSAGE(sigOK, strprintf("VerifySignature %d %d", i, j));
else
@ -120,6 +121,7 @@ BOOST_AUTO_TEST_CASE(sign)
txTo[i].vin[0].scriptSig = sigSave;
}
}
}
BOOST_AUTO_TEST_CASE(norecurse)
{

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@ -7,6 +7,7 @@
#include "test/test_bitcoin.h"
#include "clientversion.h"
#include "checkqueue.h"
#include "consensus/validation.h"
#include "core_io.h"
#include "key.h"
@ -153,6 +154,7 @@ BOOST_AUTO_TEST_CASE(tx_valid)
BOOST_CHECK_MESSAGE(CheckTransaction(tx, state), strTest);
BOOST_CHECK(state.IsValid());
PrecomputedTransactionData txdata(tx);
for (unsigned int i = 0; i < tx.vin.size(); i++)
{
if (!mapprevOutScriptPubKeys.count(tx.vin[i].prevout))
@ -168,7 +170,7 @@ BOOST_AUTO_TEST_CASE(tx_valid)
unsigned int verify_flags = ParseScriptFlags(test[2].get_str());
const CScriptWitness *witness = (i < tx.wit.vtxinwit.size()) ? &tx.wit.vtxinwit[i].scriptWitness : NULL;
BOOST_CHECK_MESSAGE(VerifyScript(tx.vin[i].scriptSig, mapprevOutScriptPubKeys[tx.vin[i].prevout],
witness, verify_flags, TransactionSignatureChecker(&tx, i, amount), &err),
witness, verify_flags, TransactionSignatureChecker(&tx, i, amount, txdata), &err),
strTest);
BOOST_CHECK_MESSAGE(err == SCRIPT_ERR_OK, ScriptErrorString(err));
}
@ -237,6 +239,7 @@ BOOST_AUTO_TEST_CASE(tx_invalid)
CValidationState state;
fValid = CheckTransaction(tx, state) && state.IsValid();
PrecomputedTransactionData txdata(tx);
for (unsigned int i = 0; i < tx.vin.size() && fValid; i++)
{
if (!mapprevOutScriptPubKeys.count(tx.vin[i].prevout))
@ -252,7 +255,7 @@ BOOST_AUTO_TEST_CASE(tx_invalid)
}
const CScriptWitness *witness = (i < tx.wit.vtxinwit.size()) ? &tx.wit.vtxinwit[i].scriptWitness : NULL;
fValid = VerifyScript(tx.vin[i].scriptSig, mapprevOutScriptPubKeys[tx.vin[i].prevout],
witness, verify_flags, TransactionSignatureChecker(&tx, i, amount), &err);
witness, verify_flags, TransactionSignatureChecker(&tx, i, amount, txdata), &err);
}
BOOST_CHECK_MESSAGE(!fValid, strTest);
BOOST_CHECK_MESSAGE(err != SCRIPT_ERR_OK, ScriptErrorString(err));
@ -419,6 +422,86 @@ void ReplaceRedeemScript(CScript& script, const CScript& redeemScript)
script = PushAll(stack);
}
BOOST_AUTO_TEST_CASE(test_big_witness_transaction) {
CMutableTransaction mtx;
mtx.nVersion = 1;
CKey key;
key.MakeNewKey(false);
CBasicKeyStore keystore;
keystore.AddKeyPubKey(key, key.GetPubKey());
CKeyID hash = key.GetPubKey().GetID();
CScript scriptPubKey = CScript() << OP_0 << std::vector<unsigned char>(hash.begin(), hash.end());
vector<int> sigHashes;
sigHashes.push_back(SIGHASH_NONE | SIGHASH_ANYONECANPAY);
sigHashes.push_back(SIGHASH_SINGLE | SIGHASH_ANYONECANPAY);
sigHashes.push_back(SIGHASH_ALL | SIGHASH_ANYONECANPAY);
sigHashes.push_back(SIGHASH_NONE);
sigHashes.push_back(SIGHASH_SINGLE);
sigHashes.push_back(SIGHASH_ALL);
// create a big transaction of 4500 inputs signed by the same key
for(uint32_t ij = 0; ij < 4500; ij++) {
uint32_t i = mtx.vin.size();
uint256 prevId;
prevId.SetHex("0000000000000000000000000000000000000000000000000000000000000100");
COutPoint outpoint(prevId, i);
mtx.vin.resize(mtx.vin.size() + 1);
mtx.vin[i].prevout = outpoint;
mtx.vin[i].scriptSig = CScript();
mtx.vout.resize(mtx.vout.size() + 1);
mtx.vout[i].nValue = 1000;
mtx.vout[i].scriptPubKey = CScript() << OP_1;
}
// sign all inputs
for(uint32_t i = 0; i < mtx.vin.size(); i++) {
bool hashSigned = SignSignature(keystore, scriptPubKey, mtx, i, 1000, sigHashes.at(i % sigHashes.size()));
assert(hashSigned);
}
CTransaction tx;
CDataStream ssout(SER_NETWORK, PROTOCOL_VERSION);
WithOrVersion(&ssout, 0) << mtx;
WithOrVersion(&ssout, 0) >> tx;
// check all inputs concurrently, with the cache
PrecomputedTransactionData txdata(tx);
boost::thread_group threadGroup;
CCheckQueue<CScriptCheck> scriptcheckqueue(128);
CCheckQueueControl<CScriptCheck> control(&scriptcheckqueue);
for (int i=0; i<20; i++)
threadGroup.create_thread(boost::bind(&CCheckQueue<CScriptCheck>::Thread, boost::ref(scriptcheckqueue)));
CCoins coins;
coins.nVersion = 1;
coins.fCoinBase = false;
for(uint32_t i = 0; i < mtx.vin.size(); i++) {
CTxOut txout;
txout.nValue = 1000;
txout.scriptPubKey = scriptPubKey;
coins.vout.push_back(txout);
}
for(uint32_t i = 0; i < mtx.vin.size(); i++) {
std::vector<CScriptCheck> vChecks;
CScriptCheck check(coins, tx, i, SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS, false, &txdata);
vChecks.push_back(CScriptCheck());
check.swap(vChecks.back());
control.Add(vChecks);
}
bool controlCheck = control.Wait();
assert(controlCheck);
threadGroup.interrupt_all();
threadGroup.join_all();
}
BOOST_AUTO_TEST_CASE(test_witness)
{
CBasicKeyStore keystore, keystore2;