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xahaud/src/cpp/ripple/ProofOfWork.cpp

364 lines
11 KiB
C++

#include "ProofOfWork.h"
#include <string>
#include <boost/test/unit_test.hpp>
#include <boost/algorithm/string.hpp>
#include <boost/format.hpp>
#include <openssl/rand.h>
#include "Serializer.h"
#include "Log.h"
SETUP_LOG();
const uint256 ProofOfWork::sMinTarget("00000000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF");
const int ProofOfWork::sMaxIterations(1 << 23);
bool ProofOfWork::isValid() const
{
if ((mIterations <= sMaxIterations) && (mTarget >= sMinTarget))
return true;
cLog(lsWARNING) << "Invalid PoW: " << mIterations << ", " << mTarget;
return false;
}
uint64 ProofOfWork::getDifficulty(const uint256& target, int iterations)
{ // calculate the approximate number of hashes required to solve this proof of work
if ((iterations > sMaxIterations) || (target < sMinTarget))
{
cLog(lsINFO) << "Iterations:" << iterations;
cLog(lsINFO) << "MaxIterat: " << sMaxIterations;
cLog(lsINFO) << "Target: " << target;
cLog(lsINFO) << "MinTarget: " << sMinTarget;
throw std::runtime_error("invalid proof of work target/iteration");
}
// more iterations means more hashes per iteration but also a larger final hash
uint64 difficulty = iterations + (iterations / 8);
// Multiply the number of hashes needed by 256 for each leading zero byte in the difficulty
const unsigned char *ptr = target.begin();
while (*ptr == 0)
{
difficulty *= 256;
++ptr;
}
difficulty = (difficulty * 256) / (*ptr + 1);
return difficulty;
}
static uint256 getSHA512Half(const std::vector<uint256>& vec)
{
return Serializer::getSHA512Half(vec.front().begin(), vec.size() * (256 / 8));
}
uint256 ProofOfWork::solve(int maxIterations) const
{
if (!isValid())
throw std::runtime_error("invalid proof of work target/iteration");
uint256 nonce;
getRand(nonce.begin(), nonce.size());
std::vector<uint256> buf2;
buf2.resize(mIterations);
std::vector<uint256> buf1;
buf1.resize(3);
buf1[0] = mChallenge;
while (maxIterations > 0)
{
buf1[1] = nonce;
buf1[2].zero();
for (int i = (mIterations - 1); i >= 0; --i)
{
buf1[2] = getSHA512Half(buf1);
buf2[i] = buf1[2];
}
if (getSHA512Half(buf2) <= mTarget)
return nonce;
++nonce;
--maxIterations;
}
return uint256();
}
bool ProofOfWork::checkSolution(const uint256& solution) const
{
if (mIterations > sMaxIterations)
return false;
std::vector<uint256> buf1;
buf1.push_back(mChallenge);
buf1.push_back(solution);
buf1.push_back(uint256());
std::vector<uint256> buf2;
buf2.resize(mIterations);
for (int i = (mIterations - 1); i >= 0; --i)
{
buf1[2] = getSHA512Half(buf1);
buf2[i] = buf1[2];
}
return getSHA512Half(buf2) <= mTarget;
}
ProofOfWorkGenerator::ProofOfWorkGenerator() : mValidTime(180)
{
setDifficulty(1);
getRand(mSecret.begin(), mSecret.size());
}
ProofOfWork ProofOfWorkGenerator::getProof()
{
// challenge - target - iterations - time - validator
static boost::format f("%s-%s-%d-%d");
int now = static_cast<int>(time(NULL) / 4);
uint256 challenge;
getRand(challenge.begin(), challenge.size());
boost::mutex::scoped_lock sl(mLock);
std::string s = boost::str(boost::format(f) % challenge.GetHex() % mTarget.GetHex() % mIterations % now);
std::string c = mSecret.GetHex() + s;
s += "-" + Serializer::getSHA512Half(c).GetHex();
return ProofOfWork(s, mIterations, challenge, mTarget);
}
POWResult ProofOfWorkGenerator::checkProof(const std::string& token, const uint256& solution)
{ // challenge - target - iterations - time - validator
std::vector<std::string> fields;
boost::split(fields, token, boost::algorithm::is_any_of("-"));
if (fields.size() != 5)
{
cLog(lsDEBUG) << "PoW " << token << " is corrupt";
return powCORRUPT;
}
std::string v = mSecret.GetHex() + fields[0] + "-" + fields[1] + "-" + fields[2] + "-" + fields[3];
if (fields[4] != Serializer::getSHA512Half(v).GetHex())
{
cLog(lsDEBUG) << "PoW " << token << " has a bad token";
return powCORRUPT;
}
uint256 challenge, target;
challenge.SetHex(fields[0]);
target.SetHex(fields[1]);
time_t t = lexical_cast_s<time_t>(fields[3]);
time_t now = time(NULL);
int iterations = lexical_cast_s<int>(fields[2]);
{
boost::mutex::scoped_lock sl(mLock);
if ((t * 4) > (now + mValidTime))
{
cLog(lsDEBUG) << "PoW " << token << " has expired";
return powEXPIRED;
}
if (((iterations != mIterations) || (target != mTarget)) && getPowEntry(target, iterations) < (mPowEntry - 2))
{ // difficulty has increased more than two times since PoW requested
cLog(lsINFO) << "Difficulty has increased since PoW requested";
return powTOOEASY;
}
}
ProofOfWork pow(token, iterations, challenge, target);
if (!pow.checkSolution(solution))
{
cLog(lsDEBUG) << "PoW " << token << " has a bad nonce";
return powBADNONCE;
}
{
boost::mutex::scoped_lock sl(mLock);
if (!mSolvedChallenges.insert(powMap_vt(now, challenge)).second)
{
cLog(lsDEBUG) << "PoW " << token << " has been reused";
return powREUSED;
}
}
return powOK;
}
void ProofOfWorkGenerator::sweep()
{
time_t expire = time(NULL) - mValidTime;
boost::mutex::scoped_lock sl(mLock);
do
{
powMap_t::left_map::iterator it = mSolvedChallenges.left.begin();
if (it == mSolvedChallenges.left.end())
return;
if (it->first >= expire)
return;
mSolvedChallenges.left.erase(it);
} while(1);
}
void ProofOfWorkGenerator::loadHigh()
{
time_t now = time(NULL);
boost::mutex::scoped_lock sl(mLock);
if (mLastDifficultyChange == now)
return;
if (mPowEntry == 30)
return;
++mPowEntry;
mLastDifficultyChange = now;
}
void ProofOfWorkGenerator::loadLow()
{
time_t now = time(NULL);
boost::mutex::scoped_lock sl(mLock);
if (mLastDifficultyChange == now)
return;
if (mPowEntry == 0)
return;
--mPowEntry;
mLastDifficultyChange = now;
}
struct PowEntry
{
const char *target;
int iterations;
};
PowEntry PowEntries[31] =
{ // target iterations hashes memory
{ "0CFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 65536 }, // 1451874, 2 MB
{ "0CFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 98304 }, // 2177811, 3 MB
{ "07FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 98304 }, // 3538944, 3 MB
{ "0CFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 196608}, // 4355623, 6 MB
{ "07FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 131072}, // 4718592, 4 MB
{ "0CFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 262144}, // 5807497, 8 MB
{ "07FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 196608}, // 7077888, 6 MB
{ "07FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 262144}, // 9437184, 8 MB
{ "07FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 393216}, // 14155776, 12MB
{ "03FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 393216}, // 28311552, 12MB
{ "00CFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 262144}, // 92919965, 8 MB
{ "00CFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 393216}, // 139379948, 12MB
{ "007FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 262144}, // 150994944, 8 MB
{ "007FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 393216}, // 226492416, 12MB
{ "000CFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 49152 }, // 278759896, 1.5MB
{ "003FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 262144}, // 301989888, 8 MB
{ "003FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 393216}, // 452984832, 12MB
{ "0007FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 98304 }, // 905969664, 3 MB
{ "000CFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 196608}, // 1115039586, 6 MB
{ "000CFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 262144}, // 1486719448 8 MB
{ "000CFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 393216}, // 2230079172 12MB
{ "0007FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 262144}, // 2415919104, 8 MB
{ "0007FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 393216}, // 3623878656, 12MB
{ "0003FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 393216}, // 7247757312, 12MB
{ "0000CFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 262144}, // 23787511177, 8 MB
{ "0000CFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 393216}, // 35681266766, 12MB
{ "00003FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 131072}, // 38654705664, 4 MB
{ "00007FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 262144}, // 38654705664, 8 MB
{ "00003FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 196608}, // 57982058496, 6 MB
{ "00007FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 393216}, // 57982058496, 12MB
{ "00003FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 262144}, // 77309411328, 8 MB
};
int ProofOfWorkGenerator::getPowEntry(const uint256& target, int iterations)
{
for (int i = 0; i < 31; ++i)
if (PowEntries[i].iterations == iterations)
{
uint256 t;
t.SetHex(PowEntries[i].target);
if (t == target)
return i;
}
return -1;
}
void ProofOfWorkGenerator::setDifficulty(int i)
{
assert((i >= 0) && (i <= 30));
time_t now = time(NULL);
boost::mutex::scoped_lock sl(mLock);
mPowEntry = i;
mIterations = PowEntries[i].iterations;
mTarget.SetHex(PowEntries[i].target);
mLastDifficultyChange = now;
}
BOOST_AUTO_TEST_SUITE(ProofOfWork_suite)
BOOST_AUTO_TEST_CASE( ProofOfWork_test )
{
ProofOfWorkGenerator gen;
ProofOfWork pow = gen.getProof();
cLog(lsINFO) << "Estimated difficulty: " << pow.getDifficulty();
uint256 solution = pow.solve(16777216);
if (solution.isZero())
BOOST_FAIL("Unable to solve proof of work");
if (!pow.checkSolution(solution))
BOOST_FAIL("Solution did not check");
cLog(lsDEBUG) << "A bad nonce error is expected";
POWResult r = gen.checkProof(pow.getToken(), uint256());
if (r != powBADNONCE)
{
Log(lsFATAL) << "POWResult = " << static_cast<int>(r);
BOOST_FAIL("Empty solution didn't show bad nonce");
}
if (gen.checkProof(pow.getToken(), solution) != powOK)
BOOST_FAIL("Solution did not check with issuer");
cLog(lsDEBUG) << "A reused nonce error is expected";
if (gen.checkProof(pow.getToken(), solution) != powREUSED)
BOOST_FAIL("Reuse solution not detected");
#ifdef SOLVE_POWS
for (int i = 0; i < 12; ++i)
{
gen.setDifficulty(i);
ProofOfWork pow = gen.getProof();
cLog(lsINFO) << "Level: " << i << ", Estimated difficulty: " << pow.getDifficulty();
uint256 solution = pow.solve(131072);
if (solution.isZero())
cLog(lsINFO) << "Giving up";
else
{
cLog(lsINFO) << "Solution found";
if (gen.checkProof(pow.getToken(), solution) != powOK)
{
cLog(lsFATAL) << "Solution fails";
}
}
}
#endif
}
BOOST_AUTO_TEST_SUITE_END()
// vim:ts=4