elements/src/pow.cpp
2018-05-11 09:24:16 -04:00

125 lines
3.8 KiB
C++

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2016 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 "core_io.h"
#include "hash.h"
#include "keystore.h"
#include "primitives/block.h"
#include "primitives/bitcoin/block.h"
#include "script/generic.hpp"
#include "script/standard.h"
#include "uint256.h"
#ifdef ENABLE_WALLET
#include "wallet/wallet.h"
#endif
CScript CombineBlockSignatures(const CBlockHeader& header, const CScript& scriptSig1, const CScript& scriptSig2)
{
SignatureData sig1(scriptSig1);
SignatureData sig2(scriptSig2);
return GenericCombineSignatures(header.proof.challenge, header, sig1, sig2).scriptSig;
}
bool CheckChallenge(const CBlockHeader& block, const CBlockIndex& indexLast, const Consensus::Params& params)
{
return block.proof.challenge == indexLast.proof.challenge;
}
void ResetChallenge(CBlockHeader& block, const CBlockIndex& indexLast, const Consensus::Params& params)
{
block.proof.challenge = indexLast.proof.challenge;
}
bool CheckBitcoinProof(uint256 hash, unsigned int nBits)
{
bool fNegative;
bool fOverflow;
arith_uint256 bnTarget;
bnTarget.SetCompact(nBits, &fNegative, &fOverflow);
// Check range
if (fNegative || bnTarget == 0 || fOverflow || bnTarget > UintToArith256(Params().GetConsensus().parentChainPowLimit))
return false;
// Check proof of work matches claimed amount
if (UintToArith256(hash) > bnTarget)
return false;
return true;
}
bool CheckProof(const CBlockHeader& block, const Consensus::Params& params)
{
if (block.GetHash() == params.hashGenesisBlock)
return true;
// Some important anti-DoS flags.
// Note: Blockhashes do not commit to the proof.
// Therefore we may have a signature be mealleated
// to stay valid, but cause the block to fail
// validation, in this case, block weight.
// In that case, the block will be marked as permanently
// invalid and not processed.
// NOTE: These have only been deemed sufficient for OP_CMS
// ANY OTHER SCRIPT TYPE MAY REQUIRE DIFFERENT FLAGS/CONSIDERATIONS
// TODO: Better design to not have to worry about script specifics
// i.e. exempt block header solution from weight limit
unsigned int proof_flags = SCRIPT_VERIFY_P2SH // Just allows P2SH evaluation
| SCRIPT_VERIFY_STRICTENC // Minimally-sized DER sigs
| SCRIPT_VERIFY_NULLDUMMY // No extra data stuffed into OP_CMS witness
| SCRIPT_VERIFY_CLEANSTACK // No extra pushes leftover in witness
| SCRIPT_VERIFY_MINIMALDATA // Pushes are minimally-sized
| SCRIPT_VERIFY_SIGPUSHONLY // Witness is push-only
| SCRIPT_VERIFY_LOW_S // Stop easiest signature fiddling
| SCRIPT_VERIFY_WITNESS; // Required for cleanstack eval in VerifyScript
return GenericVerifyScript(block.proof.solution, block.proof.challenge, proof_flags, block);
}
bool MaybeGenerateProof(CBlockHeader *pblock, CWallet *pwallet)
{
#ifdef ENABLE_WALLET
SignatureData solution(pblock->proof.solution);
bool res = GenericSignScript(*pwallet, *pblock, pblock->proof.challenge, solution);
pblock->proof.solution = solution.scriptSig;
return res;
#endif
return false;
}
void ResetProof(CBlockHeader& block)
{
block.proof.solution.clear();
}
double GetChallengeDifficulty(const CBlockIndex* blockindex)
{
return 1;
}
std::string GetChallengeStr(const CBlockIndex& block)
{
return ScriptToAsmStr(block.proof.challenge);
}
std::string GetChallengeStrHex(const CBlockIndex& block)
{
return ScriptToAsmStr(block.proof.challenge);
}
uint32_t GetNonce(const CBlockHeader& block)
{
return 1;
}
void SetNonce(CBlockHeader& block, uint32_t nNonce)
{
}