public static bool CheckKernel(IBlockRepository blockStore, ITransactionRepository trasnactionStore,
IBlockTransactionMapStore mapStore, StakeChain stakeChain,
ChainedBlock pindexPrev, uint nBits, long nTime, OutPoint prevout, ref long pBlockTime)
{
uint256 hashProofOfStake = null, targetProofOfStake = null;
var txPrev = trasnactionStore.Get(prevout.Hash);
if (txPrev == null)
{
return(false);
}
// Read block header
var blockHashPrev = mapStore.GetBlockHash(prevout.Hash);
var block = blockHashPrev == null ? null : blockStore.GetBlock(blockHashPrev);
if (block == null)
{
return(false);
}
if (IsProtocolV3((int)nTime))
{
int nDepth = 0;
if (IsConfirmedInNPrevBlocks(blockStore, txPrev, pindexPrev, StakeMinConfirmations - 1, ref nDepth))
{
return(false); // tx.DoS(100, error("CheckProofOfStake() : tried to stake at depth %d", nDepth + 1));
}
}
else
{
var nTimeBlockFrom = block.Header.Time;
if (nTimeBlockFrom + StakeMinAge > nTime)
{
return(false); // error("CheckProofOfStake() : min age violation");
}
}
var prevBlockStake = stakeChain.Get(pindexPrev.HashBlock);
if (prevBlockStake == null)
{
return(false); // the stake proof of the previous block is not set
}
// todo: check this unclear logic
//if (pBlockTime)
// pBlockTime = block.Header.Time;
return(CheckStakeKernelHash(pindexPrev, nBits, block, txPrev, prevBlockStake, prevout, (uint)nTime, out hashProofOfStake, out targetProofOfStake, false));
}
// Check kernel hash target and coinstake signature
public static bool CheckProofOfStake(IBlockRepository blockStore, ITransactionRepository trasnactionStore, IBlockTransactionMapStore mapStore,
ChainedBlock pindexPrev, BlockStake prevBlockStake, Transaction tx, uint nBits, out uint256 hashProofOfStake, out uint256 targetProofOfStake)
{
targetProofOfStake = null; hashProofOfStake = null;
// todo: Comments on this mehtod:
// the store objects (IBlockRepository and ITransactionRepository) should be a singleton instance of
// the BlockValidator and would be initiated as part of a Dependency Injection freamwork
if (!tx.IsCoinStake)
{
return(false); // error("CheckProofOfStake() : called on non-coinstake %s", tx.GetHash().ToString());
}
// Kernel (input 0) must match the stake hash target per coin age (nBits)
var txIn = tx.Inputs[0];
// First try finding the previous transaction in database
var txPrev = trasnactionStore.Get(txIn.PrevOut.Hash);
if (txPrev == null)
{
return(false); // tx.DoS(1, error("CheckProofOfStake() : INFO: read txPrev failed")); // previous transaction not in main chain, may occur during initial download
}
// Verify signature
if (!VerifySignature(txPrev, tx, 0, ScriptVerify.None))
{
return(false); // tx.DoS(100, error("CheckProofOfStake() : VerifySignature failed on coinstake %s", tx.GetHash().ToString()));
}
// Read block header
var blockHashPrev = mapStore.GetBlockHash(txIn.PrevOut.Hash);
var block = blockHashPrev == null ? null : blockStore.GetBlock(blockHashPrev);
if (block == null)
{
return(false); //fDebug? error("CheckProofOfStake() : read block failed") : false; // unable to read block of previous transaction
}
// Min age requirement
if (IsProtocolV3((int)tx.Time))
{
int nDepth = 0;
if (IsConfirmedInNPrevBlocks(blockStore, txPrev, pindexPrev, StakeMinConfirmations - 1, ref nDepth))
{
return(false); // tx.DoS(100, error("CheckProofOfStake() : tried to stake at depth %d", nDepth + 1));
}
}
else
{
var nTimeBlockFrom = block.Header.Time;
if (nTimeBlockFrom + StakeMinAge > tx.Time)
{
return(false); // error("CheckProofOfStake() : min age violation");
}
}
if (!CheckStakeKernelHash(pindexPrev, nBits, block, txPrev, prevBlockStake, txIn.PrevOut, tx.Time, out hashProofOfStake, out targetProofOfStake, false))
{
return(false); // tx.DoS(1, error("CheckProofOfStake() : INFO: check kernel failed on coinstake %s, hashProof=%s", tx.GetHash().ToString(), hashProofOfStake.ToString())); // may occur during initial download or if behind on block chain sync
}
return(true);
}
public const uint ModifierInterval = 10 * 60; // time to elapse before new modifier is computed
public static bool CheckAndComputeStake(IBlockRepository blockStore, ITransactionRepository trasnactionStore, IBlockTransactionMapStore mapStore, StakeChain stakeChain,
ChainBase chainIndex, ChainedBlock pindex, Block block, out BlockStake blockStake)
{
if (block.GetHash() != pindex.HashBlock)
{
throw new ArgumentException();
}
blockStake = new BlockStake(block);
uint256 hashProof = null;
// Verify hash target and signature of coinstake tx
if (BlockStake.IsProofOfStake(block))
{
var pindexPrev = pindex.Previous;
var prevBlockStake = stakeChain.Get(pindexPrev.HashBlock);
if (prevBlockStake == null)
{
return(false); // the stake proof of the previous block is not set
}
uint256 targetProofOfStake;
if (!CheckProofOfStake(blockStore, trasnactionStore, mapStore, pindexPrev, prevBlockStake, block.Transactions[1],
pindex.Header.Bits.ToCompact(), out hashProof, out targetProofOfStake))
{
return(false); // error("AcceptBlock() : check proof-of-stake failed for block %s", hash.ToString());
}
}
// PoW is checked in CheckBlock()
if (BlockStake.IsProofOfWork(block))
{
hashProof = pindex.Header.GetPoWHash();
}
// todo: is this the same as chain work?
// compute chain trust score
//pindexNew.nChainTrust = (pindexNew->pprev ? pindexNew->pprev->nChainTrust : 0) + pindexNew->GetBlockTrust();
// compute stake entropy bit for stake modifier
if (!blockStake.SetStakeEntropyBit(blockStake.GetStakeEntropyBit()))
{
return(false); //error("AddToBlockIndex() : SetStakeEntropyBit() failed");
}
// Record proof hash value
blockStake.HashProof = hashProof;
// compute stake modifier
return(ComputeStakeModifier(chainIndex, pindex, blockStake, stakeChain));
}
// ppcoin: total coin age spent in transaction, in the unit of coin-days.
// Only those coins meeting minimum age requirement counts. As those
// transactions not in main chain are not currently indexed so we
// might not find out about their coin age. Older transactions are
// guaranteed to be in main chain by sync-checkpoint. This rule is
// introduced to help nodes establish a consistent view of the coin
// age (trust score) of competing branches.
public static bool GetCoinAge(IBlockRepository blockStore, ITransactionRepository trasnactionStore, IBlockTransactionMapStore mapStore,
Transaction trx, ChainedBlock pindexPrev, out ulong nCoinAge)
{
BigInteger bnCentSecond = BigInteger.Zero; // coin age in the unit of cent-seconds
nCoinAge = 0;
if (trx.IsCoinBase)
{
return(true);
}
foreach (var txin in trx.Inputs)
{
// First try finding the previous transaction in database
Transaction txPrev = trasnactionStore.Get(txin.PrevOut.Hash);
if (txPrev == null)
{
continue; // previous transaction not in main chain
}
if (trx.Time < txPrev.Time)
{
return(false); // Transaction timestamp violation
}
if (IsProtocolV3((int)trx.Time))
{
int nSpendDepth = 0;
if (IsConfirmedInNPrevBlocks(blockStore, txPrev, pindexPrev, StakeMinConfirmations - 1, ref nSpendDepth))
{
//LogPrint("coinage", "coin age skip nSpendDepth=%d\n", nSpendDepth + 1);
continue; // only count coins meeting min confirmations requirement
}
}
else
{
// Read block header
var block = blockStore.GetBlock(txPrev.GetHash());
if (block == null)
{
return(false); // unable to read block of previous transaction
}
if (block.Header.Time + StakeMinAge > trx.Time)
{
continue; // only count coins meeting min age requirement
}
}
long nValueIn = txPrev.Outputs[txin.PrevOut.N].Value;
var multiplier = BigInteger.ValueOf((trx.Time - txPrev.Time) / CENT);
bnCentSecond = bnCentSecond.Add(BigInteger.ValueOf(nValueIn).Multiply(multiplier));
//bnCentSecond += new BigInteger(nValueIn) * (trx.Time - txPrev.Time) / CENT;
//LogPrint("coinage", "coin age nValueIn=%d nTimeDiff=%d bnCentSecond=%s\n", nValueIn, nTime - txPrev.nTime, bnCentSecond.ToString());
}
BigInteger bnCoinDay = bnCentSecond.Multiply(BigInteger.ValueOf(CENT / COIN / (24 * 60 * 60)));
//BigInteger bnCoinDay = bnCentSecond * CENT / COIN / (24 * 60 * 60);
//LogPrint("coinage", "coin age bnCoinDay=%s\n", bnCoinDay.ToString());
nCoinAge = new Target(bnCoinDay).ToCompact();
return(true);
}
