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pow.cpp
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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include "pow.h"
#include "arith_uint256.h"
#include "chain.h"
#include "chainparams.h"
#include "crypto/equihash.h"
#include "primitives/block.h"
#include "streams.h"
#include "uint256.h"
#include "util.h"
#include "sodium.h"
unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHeader *pblock, const Consensus::Params& params)
{
unsigned int nProofOfWorkLimit = UintToArith256(params.powLimit).GetCompact();
// Genesis block
if (pindexLast == NULL )
return nProofOfWorkLimit;
// Find the first block in the averaging interval
const CBlockIndex* pindexFirst = pindexLast;
arith_uint256 bnTot {0};
for (int i = 0; pindexFirst && i < params.nPowAveragingWindow; i++) {
arith_uint256 bnTmp;
bnTmp.SetCompact(pindexFirst->nBits);
bnTot += bnTmp;
pindexFirst = pindexFirst->pprev;
}
// Check we have enough blocks
if (pindexFirst == NULL)
return nProofOfWorkLimit;
arith_uint256 bnAvg {bnTot / params.nPowAveragingWindow};
return CalculateNextWorkRequired(bnAvg, pindexLast->GetMedianTimePast(), pindexFirst->GetMedianTimePast(), params);
}
unsigned int CalculateNextWorkRequired(arith_uint256 bnAvg,
int64_t nLastBlockTime, int64_t nFirstBlockTime,
const Consensus::Params& params)
{
// Limit adjustment step
// Use medians to prevent time-warp attacks
int64_t nActualTimespan = nLastBlockTime - nFirstBlockTime;
LogPrint("pow", " nActualTimespan = %d before dampening\n", nActualTimespan);
nActualTimespan = params.AveragingWindowTimespan() + (nActualTimespan - params.AveragingWindowTimespan())/4;
LogPrint("pow", " nActualTimespan = %d before bounds\n", nActualTimespan);
if (nActualTimespan < params.MinActualTimespan())
nActualTimespan = params.MinActualTimespan();
if (nActualTimespan > params.MaxActualTimespan())
nActualTimespan = params.MaxActualTimespan();
// Retarget
const arith_uint256 bnPowLimit = UintToArith256(params.powLimit);
arith_uint256 bnNew {bnAvg};
bnNew /= params.AveragingWindowTimespan();
bnNew *= nActualTimespan;
if (bnNew > bnPowLimit)
bnNew = bnPowLimit;
/// debug print
LogPrint("pow", "GetNextWorkRequired RETARGET\n");
LogPrint("pow", "params.AveragingWindowTimespan() = %d nActualTimespan = %d\n", params.AveragingWindowTimespan(), nActualTimespan);
LogPrint("pow", "Current average: %08x %s\n", bnAvg.GetCompact(), bnAvg.ToString());
LogPrint("pow", "After: %08x %s\n", bnNew.GetCompact(), bnNew.ToString());
return bnNew.GetCompact();
}
bool CheckEquihashSolution(const CBlockHeader *pblock, const CChainParams& params)
{
unsigned int n = params.EquihashN();
unsigned int k = params.EquihashK();
// Hash state
crypto_generichash_blake2b_state state;
EhInitialiseState(n, k, state);
// I = the block header minus nonce and solution.
CEquihashInput I{*pblock};
// I||V
CDataStream ss(SER_NETWORK, PROTOCOL_VERSION);
ss << I;
ss << pblock->nNonce;
// H(I||V||...
crypto_generichash_blake2b_update(&state, (unsigned char*)&ss[0], ss.size());
bool isValid;
EhIsValidSolution(n, k, state, pblock->nSolution, isValid);
if (!isValid)
return error("CheckEquihashSolution(): invalid solution");
return true;
}
int32_t komodo_chosennotary(int32_t *notaryidp,int32_t height,uint8_t *pubkey33);
int32_t komodo_is_special(int32_t height,uint8_t pubkey33[33]);
int32_t komodo_currentheight();
CBlockIndex *komodo_chainactive(int32_t height);
int8_t komodo_minerid(int32_t height,uint8_t *pubkey33);
void komodo_index2pubkey33(uint8_t *pubkey33,CBlockIndex *pindex,int32_t height);
extern int32_t KOMODO_CHOSEN_ONE;
#define KOMODO_ELECTION_GAP 2000
int32_t komodo_eligiblenotary(uint8_t pubkeys[66][33],int32_t *mids,int32_t *nonzpkeysp,int32_t height);
int32_t KOMODO_LOADINGBLOCKS;
extern std::string NOTARY_PUBKEY;
bool CheckProofOfWork(int32_t height,uint8_t *pubkey33,uint256 hash, unsigned int nBits, const Consensus::Params& params)
{
extern int32_t KOMODO_REWIND;
bool fNegative,fOverflow; int32_t i,nonzpkeys=0,nonz=0,special=0,special2=0,notaryid=-1,duplicate,flag = 0, mids[66];
arith_uint256 bnTarget; CBlockIndex *pindex; uint8_t pubkeys[66][33];
bnTarget.SetCompact(nBits, &fNegative, &fOverflow);
if ( height == 0 )
height = komodo_currentheight() + 1;
special = komodo_chosennotary(¬aryid,height,pubkey33);
flag = komodo_eligiblenotary(pubkeys,mids,&nonzpkeys,height);
if ( height > 34000 ) // 0 -> non-special notary
{
for (i=0; i<33; i++)
{
if ( pubkey33[i] != 0 )
nonz++;
}
if ( nonz == 0 )
return(true); // will come back via different path with pubkey set
special2 = komodo_is_special(height,pubkey33);
if ( notaryid >= 0 )
{
if ( height > 10000 && height < 80000 && (special != 0 || special2 > 0) )
flag = 1;
else if ( height >= 80000 && height < 108000 && special2 > 0 )
flag = 1;
else if ( height >= 108000 && special2 > 0 )
flag = ((height % KOMODO_ELECTION_GAP) > 64 || (height % KOMODO_ELECTION_GAP) == 0);
if ( flag != 0 )
bnTarget.SetCompact(KOMODO_MINDIFF_NBITS,&fNegative,&fOverflow);
}
}
if (fNegative || bnTarget == 0 || fOverflow || bnTarget > UintToArith256(params.powLimit))
return error("CheckProofOfWork(): nBits below minimum work");
// Check proof of work matches claimed amount
if ( UintToArith256(hash) > bnTarget )
{
if ( (height < 235300 || height >= 236000) && KOMODO_LOADINGBLOCKS == 0 && height > 188000 && KOMODO_REWIND == 0 )//186269, 182507&& komodo_chainactive(height) != 0 && nonzpkeys > 0
{
int32_t i;
for (i=31; i>=0; i--)
printf("%02x",((uint8_t *)&hash)[i]);
printf(" hash vs ");
for (i=31; i>=0; i--)
printf("%02x",((uint8_t *)&bnTarget)[i]);
printf(" ht.%d REWIND.%d special.%d notaryid.%d ht.%d mod.%d error\n",height,KOMODO_REWIND,special,notaryid,height,(height % 35));
for (i=0; i<33; i++)
printf("%02x",pubkey33[i]);
printf(" <- pubkey\n");
for (i=0; i<66; i++)
printf("%d ",mids[i]);
printf(" minerids from ht.%d\n",height);
if ( notaryid >= 0 || height > 225065 )
return error("CheckProofOfWork(): hash doesn't match nBits");
}
}
return true;
}
arith_uint256 GetBlockProof(const CBlockIndex& block)
{
arith_uint256 bnTarget;
bool fNegative;
bool fOverflow;
bnTarget.SetCompact(block.nBits, &fNegative, &fOverflow);
if (fNegative || fOverflow || bnTarget == 0)
return 0;
// We need to compute 2**256 / (bnTarget+1), but we can't represent 2**256
// as it's too large for a arith_uint256. However, as 2**256 is at least as large
// as bnTarget+1, it is equal to ((2**256 - bnTarget - 1) / (bnTarget+1)) + 1,
// or ~bnTarget / (nTarget+1) + 1.
return (~bnTarget / (bnTarget + 1)) + 1;
}
int64_t GetBlockProofEquivalentTime(const CBlockIndex& to, const CBlockIndex& from, const CBlockIndex& tip, const Consensus::Params& params)
{
arith_uint256 r;
int sign = 1;
if (to.nChainWork > from.nChainWork) {
r = to.nChainWork - from.nChainWork;
} else {
r = from.nChainWork - to.nChainWork;
sign = -1;
}
r = r * arith_uint256(params.nPowTargetSpacing) / GetBlockProof(tip);
if (r.bits() > 63) {
return sign * std::numeric_limits<int64_t>::max();
}
return sign * r.GetLow64();
}