/// <inheritdoc />
public bool CheckKernel(PosRuleContext context, ChainedHeader prevChainedHeader, uint headerBits,
long transactionTime, OutPoint prevout)
{
Guard.NotNull(context, nameof(context));
Guard.NotNull(prevout, nameof(prevout));
Guard.NotNull(prevChainedHeader, nameof(prevChainedHeader));
var coins = this.coinView.FetchCoins(new[] { prevout.Hash });
if (coins == null || coins.UnspentOutputs.Length != 1)
{
this.logger.LogTrace("(-)[READ_PREV_TX_FAILED]");
ConsensusErrors.ReadTxPrevFailed.Throw();
}
var prevBlock = this.chainIndexer.GetHeader(coins.BlockHash);
if (prevBlock == null)
{
this.logger.LogTrace("(-)[REORG]");
ConsensusErrors.ReadTxPrevFailed.Throw();
}
var prevUtxo = coins.UnspentOutputs[0];
if (prevUtxo == null)
{
this.logger.LogTrace("(-)[PREV_UTXO_IS_NULL]");
ConsensusErrors.ReadTxPrevFailed.Throw();
}
if (IsConfirmedInNPrevBlocks(prevUtxo, prevChainedHeader, GetTargetDepthRequired(prevChainedHeader)))
{
this.logger.LogTrace("(-)[LOW_COIN_AGE]");
ConsensusErrors.InvalidStakeDepth.Throw();
}
var prevBlockStake = this.stakeChain.Get(prevChainedHeader.HashBlock);
if (prevBlockStake == null)
{
this.logger.LogTrace("(-)[BAD_STAKE_BLOCK]");
ConsensusErrors.BadStakeBlock.Throw();
}
return(CheckStakeKernelHash(context, headerBits, prevBlockStake.StakeModifierV2, prevUtxo, prevout,
(uint)transactionTime));
}
/// <inheritdoc />
public void CheckProofOfStake(PosRuleContext context, ChainedHeader prevChainedHeader,
BlockStake prevBlockStake, Transaction transaction, uint headerBits)
{
Guard.NotNull(context, nameof(context));
Guard.NotNull(prevChainedHeader, nameof(prevChainedHeader));
Guard.NotNull(prevBlockStake, nameof(prevBlockStake));
Guard.NotNull(transaction, nameof(transaction));
if (!transaction.IsCoinStake)
{
this.logger.LogTrace("(-)[NO_COINSTAKE]");
ConsensusErrors.NonCoinstake.Throw();
}
var txIn = transaction.Inputs[0];
var prevUtxo = context.UnspentOutputSet.AccessCoins(txIn.PrevOut.Hash);
if (prevUtxo == null)
{
this.logger.LogTrace("(-)[PREV_UTXO_IS_NULL]");
ConsensusErrors.ReadTxPrevFailed.Throw();
}
// Verify signature.
if (!VerifySignature(prevUtxo, transaction, 0, ScriptVerify.None))
{
this.logger.LogTrace("(-)[BAD_SIGNATURE]");
ConsensusErrors.CoinstakeVerifySignatureFailed.Throw();
}
// Min age requirement.
if (IsConfirmedInNPrevBlocks(prevUtxo, prevChainedHeader, GetTargetDepthRequired(prevChainedHeader)))
{
this.logger.LogTrace("(-)[BAD_STAKE_DEPTH]");
ConsensusErrors.InvalidStakeDepth.Throw();
}
if (!CheckStakeKernelHash(context, headerBits, prevBlockStake.StakeModifierV2, prevUtxo, txIn.PrevOut,
context.ValidationContext.ChainedHeaderToValidate.Header.Time))
{
this.logger.LogTrace("(-)[INVALID_STAKE_HASH_TARGET]");
ConsensusErrors.StakeHashInvalidTarget.Throw();
}
}
/// <inheritdoc />
public bool CheckStakeKernelHash(PosRuleContext context, uint headerBits, uint256 prevStakeModifier,
UnspentOutputs stakingCoins, OutPoint prevout, uint transactionTime)
{
Guard.NotNull(context, nameof(context));
Guard.NotNull(prevout, nameof(prevout));
Guard.NotNull(stakingCoins, nameof(stakingCoins));
if (transactionTime < stakingCoins.Time)
{
this.logger.LogDebug("Coinstake transaction timestamp {0} is lower than it's own UTXO timestamp {1}.",
transactionTime, stakingCoins.Time);
this.logger.LogTrace("(-)[BAD_STAKE_TIME]");
ConsensusErrors.StakeTimeViolation.Throw();
}
// Base target.
var target = new Target(headerBits).ToBigInteger();
// TODO: Investigate:
// The POS protocol should probably put a limit on the max amount that can be staked
// not a hard limit but a limit that allow any amount to be staked with a max weight value.
// the max weight should not exceed the max uint256 array size (array size = 32).
// Weighted target.
var valueIn = stakingCoins.Outputs[prevout.N].Value.Satoshi;
var weight = BigInteger.ValueOf(valueIn);
var weightedTarget = target.Multiply(weight);
context.TargetProofOfStake = ToUInt256(weightedTarget);
this.logger.LogDebug("POS target is '{0}', weighted target for {1} coins is '{2}'.", ToUInt256(target),
valueIn, context.TargetProofOfStake);
if (this.legacytimefield == null)
{
this.legacytimefield =
this.network.Consensus.ConsensusFactory.CreateTransaction() is IPosTransactionWithTime;
}
// Calculate hash.
using (var ms = new MemoryStream())
{
var serializer = new BitcoinStream(ms, true);
serializer.ReadWrite(prevStakeModifier);
if (this.legacytimefield == true) // to stay compatible with legacy ODN
{
serializer.ReadWrite(stakingCoins.Time);
}
serializer.ReadWrite(prevout.Hash);
serializer.ReadWrite(prevout.N);
serializer.ReadWrite(transactionTime);
context.HashProofOfStake = Hashes.Hash256(ms.ToArray());
}
this.logger.LogDebug("Stake modifier V2 is '{0}', hash POS is '{1}'.", prevStakeModifier,
context.HashProofOfStake);
// Now check if proof-of-stake hash meets target protocol.
var hashProofOfStakeTarget = new BigInteger(1, context.HashProofOfStake.ToBytes(false));
if (hashProofOfStakeTarget.CompareTo(weightedTarget) > 0)
{
this.logger.LogTrace("(-)[TARGET_MISSED]");
return(false);
}
return(true);
}
