/// <summary>
/// Mines a new genesis block, to use with a new network.
/// Typically, 3 such genesis blocks need to be created when bootstrapping a new coin: for Main, Test and Reg networks.
/// </summary>
/// <param name="consensusFactory">
/// The consensus factory used to create transactions and blocks.
/// Use <see cref="PosConsensusFactory"/> for proof-of-stake based networks.
/// </param>
/// <param name="coinbaseText">
/// Traditionally a news headline from the day of the launch, but could be any string or link.
/// This will be inserted in the input coinbase transaction script.
/// It should be shorter than 92 characters.
/// </param>
/// <param name="target">
/// The difficulty target under which the hash of the block need to be.
/// Some more details: As an example, the target for the Stratis Main network is 00000fffffffffffffffffffffffffffffffffffffffffffffffffffffffffff.
/// To make it harder to mine the genesis block, have more zeros at the beginning (keeping the length the same). This will make the target smaller, so finding a number under it will be more difficult.
/// To make it easier to mine the genesis block ,do the opposite. Example of an easy one: 00ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff.
/// Make the Test and Reg targets ones easier to find than the Main one so that you don't wait too long to mine the genesis block.
/// </param>
/// <param name="genesisReward">
/// Specify how many coins to put in the genesis transaction's output. These coins are unspendable.
/// </param>
/// <param name="version">
/// The version of the transaction and the block header set in the genesis block.
/// </param>
/// <example>
/// The following example shows the creation of a genesis block.
/// <code>
/// Block genesis = MineGenesisBlock(new PosConsensusFactory(), "Some topical headline.", new Target(new uint256("000fffff00000000000000000000000000000000000000000000000000000000")), Money.Coins(50m));
/// BlockHeader header = genesis.Header;
/// Console.WriteLine("Make a note of the following values:");
/// Console.WriteLine("bits: " + header.Bits);
/// Console.WriteLine("nonce: " + header.Nonce);
/// Console.WriteLine("time: " + header.Time);
/// Console.WriteLine("version: " + header.Version);
/// Console.WriteLine("hash: " + header.GetHash());
/// Console.WriteLine("merkleroot: " + header.HashMerkleRoot);
/// </code>
/// </example>
/// <returns>A genesis block.</returns>
public static Block MineGenesisBlock(ConsensusFactory consensusFactory, string coinbaseText, Target target, Money genesisReward, int version = 1)
{
if (consensusFactory == null)
throw new ArgumentException($"Parameter '{nameof(consensusFactory)}' cannot be null. Use 'new ConsensusFactory()' for Bitcoin-like proof-of-work blockchains and 'new PosConsensusFactory()' for Stratis-like proof-of-stake blockchains.");
if (string.IsNullOrEmpty(coinbaseText))
throw new ArgumentException($"Parameter '{nameof(coinbaseText)}' cannot be null. Use a news headline or any other appropriate string.");
if (target == null)
throw new ArgumentException($"Parameter '{nameof(target)}' cannot be null. Example use: new Target(new uint256(\"0000ffff00000000000000000000000000000000000000000000000000000000\"))");
if (coinbaseText.Length >= 92)
throw new ArgumentException($"Parameter '{nameof(coinbaseText)}' should be shorter than 92 characters.");
if (genesisReward == null)
throw new ArgumentException($"Parameter '{nameof(genesisReward)}' cannot be null. Example use: 'Money.Coins(50m)'.");
DateTimeOffset time = DateTimeOffset.Now;
uint unixTime = Utils.DateTimeToUnixTime(time);
Transaction txNew = consensusFactory.CreateTransaction();
txNew.Version = (uint)version;
txNew.AddInput(new TxIn()
{
ScriptSig = new Script(
Op.GetPushOp(0),
new Op()
{
Code = (OpcodeType)0x1,
PushData = new[] { (byte)42 }
},
Op.GetPushOp(Encoders.ASCII.DecodeData(coinbaseText)))
});
txNew.AddOutput(new TxOut()
{
Value = genesisReward,
});
Block genesis = consensusFactory.CreateBlock();
genesis.Header.BlockTime = time;
genesis.Header.Bits = target;
genesis.Header.Nonce = 0;
genesis.Header.Version = version;
genesis.Transactions.Add(txNew);
genesis.Header.HashPrevBlock = uint256.Zero;
genesis.UpdateMerkleRoot();
// Iterate over the nonce until the proof-of-work is valid.
// This will mean the block header hash is under the target.
while (!genesis.CheckProofOfWork())
{
genesis.Header.Nonce++;
if (genesis.Header.Nonce == 0)
genesis.Header.Time++;
}
return genesis;
}
// a method to check a block, this may be moved to the full node.
public static bool CheckBlock(Block block, bool checkPow = true, bool checkMerkleRoot = true, bool checkSig = true)
{
// These are checks that are independent of context
// that can be verified before saving an orphan block.
// Size limits
if (!block.Transactions.Any() || block.GetSerializedSize() > MAX_BLOCK_SIZE)
{
return(false); // DoS(100, error("CheckBlock() : size limits failed"));
}
// Check proof of work matches claimed amount
if (checkPow && BlockStake.IsProofOfWork(block) && !block.CheckProofOfWork())
{
return(false); //DoS(50, error("CheckBlock() : proof of work failed"));
}
// Check timestamp
if (block.Header.Time > FutureDriftV2(DateTime.UtcNow.Ticks)) //GetAdjustedTime()))
{
return(false); //error("CheckBlock() : block timestamp too far in he future");
}
// First transaction must be coinbase, the rest must not be
if (!block.Transactions[0].IsCoinBase)
{
return(false); // DoS(100, error("CheckBlock() : first tx is not coinbase"));
}
if (block.Transactions.Skip(1).Any(t => t.IsCoinBase))
{
return(false); //DoS(100, error("CheckBlock() : more than one coinbase"));
}
if (BlockStake.IsProofOfStake(block))
{
// Coinbase output should be empty if proof-of-stake block
if (block.Transactions[0].Outputs.Count != 1 || !block.Transactions[0].Outputs[0].IsEmpty)
{
return(false); // DoS(100, error("CheckBlock() : coinbase output not empty for proof-of-stake block"));
}
// Second transaction must be coinstake, the rest must not be
if (!block.Transactions[1].IsCoinStake)
{
return(false); // DoS(100, error("CheckBlock() : second tx is not coinstake"));
}
if (block.Transactions.Skip(2).Any(t => t.IsCoinStake))
{
return(false); //DoS(100, error("CheckBlock() : more than one coinstake"));
}
}
// Check proof-of-stake block signature
if (checkSig && !CheckBlockSignature(block))
{
return(false); //DoS(100, error("CheckBlock() : bad proof-of-stake block signature"));
}
// Check transactions
foreach (var transaction in block.Transactions)
{
if (transaction.Check() != TransactionCheckResult.Success)
{
return(false); // DoS(tx.nDoS, error("CheckBlock() : CheckTransaction failed"));
}
// ppcoin: check transaction timestamp
if (block.Header.Time < transaction.Time)
{
return(false); // DoS(50, error("CheckBlock() : block timestamp earlier than transaction timestamp"));
}
}
// Check for duplicate txids. This is caught by ConnectInputs(),
// but catching it earlier avoids a potential DoS attack:
var set = new HashSet <uint256>();
if (block.Transactions.Select(t => t.GetHash()).Any(h => !set.Add(h)))
{
return(false); //DoS(100, error("CheckBlock() : duplicate transaction"));
}
// todo: check if this is legacy from older implementtions and actually needed
//uint nSigOps = 0;
//foreach (var transaction in block.Transactions)
//{
// nSigOps += GetLegacySigOpCount(transaction);
//}
//if (nSigOps > MAX_BLOCK_SIGOPS)
// return DoS(100, error("CheckBlock() : out-of-bounds SigOpCount"));
// Check merkle root
if (checkMerkleRoot && !block.CheckMerkleRoot())
{
return(false); //DoS(100, error("CheckBlock() : hashMerkleRoot mismatch"));
}
return(true);
}
