// For every cycle, a new set of keys are required for the validators. This key generation process
// is done on-chain. That means, every communication between participating nodes happen via transactions
// in the block. For example, if node A wants to send a msg to node B, then node A encrypts the
// msg with node B's public key and broadcast this as a transaction to the governance contract.
// After this transaction is added to the chain, node B can decrypt the msg and read it.
// During block execution, after every system transaction is executed, the following method
// is invoked. It evaluates the transaction and if it's keygen related, it produces
// appropriate response in form of a transaction and adds it to the pool for the addition
// in the block.
private void BlockManagerOnSystemContractInvoked(object _, InvocationContext context)
{
if (context.Receipt is null)
{
return;
}
var highestBlock = _blockSynchronizer.GetHighestBlock();
var willParticipate =
!highestBlock.HasValue ||
GovernanceContract.IsKeygenBlock(context.Receipt.Block) &&
GovernanceContract.SameCycle(highestBlock.Value, context.Receipt.Block);
if (!willParticipate)
{
Logger.LogInformation(
highestBlock != null
? $"Will not participate in keygen: highest block is {highestBlock.Value}, call block is {context.Receipt.Block}"
: $"Will not participate in keygen: highest block is null, call block is {context.Receipt.Block}"
);
}
var tx = context.Receipt.Transaction;
if (
!tx.To.Equals(ContractRegisterer.GovernanceContract) &&
!tx.To.Equals(ContractRegisterer.StakingContract)
)
{
return;
}
if (context.Receipt.Block < _blockManager.GetHeight() &&
!GovernanceContract.SameCycle(context.Receipt.Block, _blockManager.GetHeight()))
{
Logger.LogWarning(
$"System contract invoked from outdated tx: {context.Receipt.Hash}, tx block {context.Receipt.Block}, our height is {_blockManager.GetHeight()}");
return;
}
if (tx.Invocation.Length < 4)
{
return;
}
var signature = ContractEncoder.MethodSignatureAsInt(tx.Invocation);
var decoder = new ContractDecoder(tx.Invocation.ToArray());
var contractAddress = tx.To;
if (contractAddress.Equals(ContractRegisterer.GovernanceContract) && signature ==
ContractEncoder.MethodSignatureAsInt(GovernanceInterface.MethodFinishCycle))
{
Logger.LogDebug("Aborting ongoing keygen because cycle was finished");
_keyGenRepository.SaveKeyGenState(Array.Empty <byte>());
}
else if (signature == ContractEncoder.MethodSignatureAsInt(StakingInterface.MethodFinishVrfLottery))
{
Logger.LogDebug($"Detected call of StakingInterface.{StakingInterface.MethodFinishVrfLottery}");
var cycle = GovernanceContract.GetCycleByBlockNumber(context.Receipt.Block);
var data = new GovernanceContract(context).GetNextValidators();
var publicKeys =
(data ?? throw new ArgumentException("Cannot parse method args"))
.Select(x => x.ToPublicKey())
.ToArray();
Logger.LogDebug(
$"Keygen is started in cycle={cycle}, block={context.Receipt.Block} for validator set: {string.Join(",", publicKeys.Select(x => x.ToHex()))}"
);
if (!publicKeys.Contains(_privateWallet.EcdsaKeyPair.PublicKey))
{
Logger.LogWarning("Skipping validator change event since we are not new validator");
return;
}
var keygen = GetCurrentKeyGen();
if (keygen != null && keygen.Cycle == cycle)
{
throw new ArgumentException("Cannot start keygen, since one is already running");
}
if (keygen != null)
{
Logger.LogWarning($"Aborted keygen for cycle {keygen.Cycle} to start keygen for cycle {cycle}");
}
_keyGenRepository.SaveKeyGenState(Array.Empty <byte>());
var faulty = (publicKeys.Length - 1) / 3;
keygen = new TrustlessKeygen(_privateWallet.EcdsaKeyPair, publicKeys, faulty, cycle);
var commitTx = MakeCommitTransaction(keygen.StartKeygen(), cycle);
Logger.LogTrace($"Produced commit tx with hash: {commitTx.Hash.ToHex()}");
if (willParticipate)
{
Logger.LogInformation($"Try to send KeyGen Commit transaction");
if (_transactionPool.Add(commitTx) is var error && error != OperatingError.Ok)
{
Logger.LogError($"Error creating commit transaction ({commitTx.Hash.ToHex()}): {error}");
}
else
{
Logger.LogInformation($"KeyGen Commit transaction sent");
}
}
Logger.LogDebug($"Saving keygen {keygen.ToBytes().ToHex()}");
_keyGenRepository.SaveKeyGenState(keygen.ToBytes());
}