core: first few round will not have DKG (#455)

* core: Add DKGDelayRound constant

* core: use constant value

* core, utils: set DKGDelayRound for utils.

* test: add dkgDelayRound to state

* core: do not run dkg and crs for round < DKGDelayRound

* fix test

17 files changed, 100 insertions, 93 deletions

diff --git a/core/blockchain.go b/core/blockchain.go
index bc9616c..03c8561 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -188,7 +188,7 @@ func (bc *blockChain) extractBlocks() (ret []*types.Block) {
 	defer bc.lock.Unlock()
 	for len(bc.confirmedBlocks) > 0 {
 		c := bc.confirmedBlocks[0]
-		if c.Position.Round > 0 && len(c.Finalization.Randomness) == 0 {
+		if c.Position.Round >= DKGDelayRound && len(c.Finalization.Randomness) == 0 {
 			break
 		}
 		c, bc.confirmedBlocks = bc.confirmedBlocks[0], bc.confirmedBlocks[1:]
@@ -502,7 +502,7 @@ func (bc *blockChain) purgeConfig() {
 
 func (bc *blockChain) verifyRandomness(
 	blockHash common.Hash, round uint64, randomness []byte) (bool, error) {
-	if round == 0 {
+	if round < DKGDelayRound {
 		return len(randomness) == 0, nil
 	}
 	v, ok, err := bc.vGetter.UpdateAndGet(round)
diff --git a/core/configuration-chain_test.go b/core/configuration-chain_test.go
index 1fe54bc..939cf65 100644
--- a/core/configuration-chain_test.go
+++ b/core/configuration-chain_test.go
@@ -202,7 +202,7 @@ func (s *ConfigurationChainTestSuite) runDKG(
 	recv := newTestCCGlobalReceiver(s)
 
 	for _, nID := range s.nIDs {
-		gov, err := test.NewGovernance(test.NewState(
+		gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
 			s.pubKeys, 100*time.Millisecond, &common.NullLogger{}, true,
 		), ConfigRoundShift)
 		s.Require().NoError(err)
@@ -271,7 +271,7 @@ func (s *ConfigurationChainTestSuite) preparePartialSignature(
 func (s *ConfigurationChainTestSuite) TestConfigurationChain() {
 	k := 4
 	n := 10
-	round := uint64(0)
+	round := DKGDelayRound
 	cfgChains := s.runDKG(k, n, round)
 
 	hash := crypto.Keccak256Hash([]byte("🌚🌝"))
@@ -316,7 +316,7 @@ func (s *ConfigurationChainTestSuite) TestConfigurationChain() {
 func (s *ConfigurationChainTestSuite) TestDKGMasterPublicKeyDelayAdd() {
 	k := 4
 	n := 10
-	round := uint64(0)
+	round := DKGDelayRound
 	lambdaDKG := 1000 * time.Millisecond
 	s.setupNodes(n)
 
@@ -325,7 +325,7 @@ func (s *ConfigurationChainTestSuite) TestDKGMasterPublicKeyDelayAdd() {
 	delayNode := s.nIDs[0]
 
 	for _, nID := range s.nIDs {
-		state := test.NewState(
+		state := test.NewState(DKGDelayRound,
 			s.pubKeys, 100*time.Millisecond, &common.NullLogger{}, true)
 		gov, err := test.NewGovernance(state, ConfigRoundShift)
 		s.Require().NoError(err)
@@ -382,7 +382,7 @@ func (s *ConfigurationChainTestSuite) TestDKGMasterPublicKeyDelayAdd() {
 func (s *ConfigurationChainTestSuite) TestDKGComplaintDelayAdd() {
 	k := 4
 	n := 10
-	round := uint64(0)
+	round := DKGDelayRound
 	lambdaDKG := 1000 * time.Millisecond
 	s.setupNodes(n)
 
@@ -390,7 +390,7 @@ func (s *ConfigurationChainTestSuite) TestDKGComplaintDelayAdd() {
 	recv := newTestCCGlobalReceiver(s)
 	recvs := make(map[types.NodeID]*testCCReceiver)
 	for _, nID := range s.nIDs {
-		state := test.NewState(
+		state := test.NewState(DKGDelayRound,
 			s.pubKeys, 100*time.Millisecond, &common.NullLogger{}, true)
 		gov, err := test.NewGovernance(state, ConfigRoundShift)
 		s.Require().NoError(err)
@@ -458,7 +458,7 @@ func (s *ConfigurationChainTestSuite) TestDKGComplaintDelayAdd() {
 func (s *ConfigurationChainTestSuite) TestMultipleTSig() {
 	k := 2
 	n := 7
-	round := uint64(0)
+	round := DKGDelayRound
 	cfgChains := s.runDKG(k, n, round)
 
 	hash1 := crypto.Keccak256Hash([]byte("Hash1"))
@@ -518,7 +518,7 @@ func (s *ConfigurationChainTestSuite) TestMultipleTSig() {
 func (s *ConfigurationChainTestSuite) TestTSigTimeout() {
 	k := 2
 	n := 7
-	round := uint64(0)
+	round := DKGDelayRound
 	cfgChains := s.runDKG(k, n, round)
 	timeout := 6 * time.Second
 
@@ -555,7 +555,7 @@ func (s *ConfigurationChainTestSuite) TestTSigTimeout() {
 func (s *ConfigurationChainTestSuite) TestDKGSignerRecoverFromDB() {
 	k := 2
 	n := 7
-	round := uint64(0)
+	round := DKGDelayRound
 	cfgChains := s.runDKG(k, n, round)
 	hash := crypto.Keccak256Hash([]byte("Hash1"))
 	// Make sure we have more than one configurationChain instance.
diff --git a/core/consensus.go b/core/consensus.go
index 25fc16d..370df72 100644
--- a/core/consensus.go
+++ b/core/consensus.go
@@ -599,25 +599,8 @@ func (con *Consensus) prepare(
 		return
 	}
 	if initRound == 0 {
-		dkgSet, err := con.nodeSetCache.GetDKGSet(initRound)
-		if err != nil {
-			return err
-		}
-		if _, exist := dkgSet[con.ID]; exist {
-			con.logger.Info("Selected as DKG set", "round", initRound)
-			go func() {
-				// Sleep until dMoment come.
-				time.Sleep(con.dMoment.Sub(time.Now().UTC()))
-				// Network is not stable upon starting. Wait some time to ensure first
-				// DKG would success. Three is a magic number.
-				time.Sleep(initConfig.MinBlockInterval * 3)
-				con.cfgModule.registerDKG(initRound, getDKGThreshold(initConfig))
-				con.event.RegisterHeight(
-					initConfig.RoundLength/4,
-					func(uint64) {
-						con.runDKG(initRound, initConfig)
-					})
-			}()
+		if DKGDelayRound == 0 {
+			panic("not implemented yet")
 		}
 	}
 	// Register events.
@@ -747,20 +730,22 @@ func (con *Consensus) initialRound(
 		return
 	default:
 	}
-	curDkgSet, err := con.nodeSetCache.GetDKGSet(round)
-	if err != nil {
-		con.logger.Error("Error getting DKG set", "round", round, "error", err)
-		curDkgSet = make(map[types.NodeID]struct{})
-	}
-	// Initiate CRS routine.
-	if _, exist := curDkgSet[con.ID]; exist {
-		con.event.RegisterHeight(
-			startHeight+config.RoundLength/2,
-			func(uint64) {
-				go func() {
-					con.runCRS(round)
-				}()
-			})
+	if round >= DKGDelayRound {
+		curDkgSet, err := con.nodeSetCache.GetDKGSet(round)
+		if err != nil {
+			con.logger.Error("Error getting DKG set", "round", round, "error", err)
+			curDkgSet = make(map[types.NodeID]struct{})
+		}
+		// Initiate CRS routine.
+		if _, exist := curDkgSet[con.ID]; exist {
+			con.event.RegisterHeight(
+				startHeight+config.RoundLength/2,
+				func(uint64) {
+					go func() {
+						con.runCRS(round)
+					}()
+				})
+		}
 	}
 	// checkCRS is a generator of checker to check if CRS for that round is
 	// ready or not.
@@ -800,6 +785,10 @@ func (con *Consensus) initialRound(
 	// Initiate DKG for this round.
 	con.event.RegisterHeight(startHeight+config.RoundLength/2, func(uint64) {
 		go func(nextRound uint64) {
+			if nextRound < DKGDelayRound {
+				con.logger.Info("Skip runDKG for round", "round", nextRound)
+				return
+			}
 			// Normally, gov.CRS would return non-nil. Use this for in case of
 			// unexpected network fluctuation and ensure the robustness.
 			if !checkWithCancel(
diff --git a/core/consensus_test.go b/core/consensus_test.go
index 1cad67b..b758c77 100644
--- a/core/consensus_test.go
+++ b/core/consensus_test.go
@@ -216,7 +216,7 @@ func (s *ConsensusTestSuite) TestDKGCRS() {
 	conn := s.newNetworkConnection()
 	prvKeys, pubKeys, err := test.NewKeys(n)
 	s.Require().NoError(err)
-	gov, err := test.NewGovernance(test.NewState(
+	gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
 		pubKeys, lambda, &common.NullLogger{}, true), ConfigRoundShift)
 	s.Require().NoError(err)
 	gov.State().RequestChange(test.StateChangeRoundLength, uint64(200))
@@ -258,7 +258,7 @@ func (s *ConsensusTestSuite) TestSyncBA() {
 	conn := s.newNetworkConnection()
 	prvKeys, pubKeys, err := test.NewKeys(4)
 	s.Require().NoError(err)
-	gov, err := test.NewGovernance(test.NewState(
+	gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
 		pubKeys, lambdaBA, &common.NullLogger{}, true), ConfigRoundShift)
 	s.Require().NoError(err)
 	prvKey := prvKeys[0]
diff --git a/core/constant.go b/core/constant.go
index 563a321..f80e1b9 100644
--- a/core/constant.go
+++ b/core/constant.go
@@ -17,9 +17,21 @@
 
 package core
 
+import "github.com/dexon-foundation/dexon-consensus/core/utils"
+
 // ConfigRoundShift refers to the difference between block's round and config
 // round derived from its state.
 //
 // For example, when round shift is 2, a block in round 0 should derive config
 // for round 2.
 const ConfigRoundShift uint64 = 2
+
+// DKGDelayRound refers to the round that first DKG is run.
+//
+// For example, when delay round is 1, new DKG will run at round 1. Round 0 will
+// have neither DKG nor CRS.
+const DKGDelayRound uint64 = 1
+
+func init() {
+	utils.SetDKGDelayRound(DKGDelayRound)
+}
diff --git a/core/dkg-tsig-protocol_test.go b/core/dkg-tsig-protocol_test.go
index 4086267..445a51c 100644
--- a/core/dkg-tsig-protocol_test.go
+++ b/core/dkg-tsig-protocol_test.go
@@ -148,7 +148,7 @@ func (s *DKGTSIGProtocolTestSuite) TestDKGTSIGProtocol() {
 	round := uint64(1)
 	_, pubKeys, err := test.NewKeys(5)
 	s.Require().NoError(err)
-	gov, err := test.NewGovernance(test.NewState(
+	gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
 		pubKeys, 100, &common.NullLogger{}, true), ConfigRoundShift)
 	s.Require().NoError(err)
 
@@ -253,7 +253,7 @@ func (s *DKGTSIGProtocolTestSuite) TestNackComplaint() {
 	round := uint64(1)
 	_, pubKeys, err := test.NewKeys(5)
 	s.Require().NoError(err)
-	gov, err := test.NewGovernance(test.NewState(
+	gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
 		pubKeys, 100, &common.NullLogger{}, true), ConfigRoundShift)
 	s.Require().NoError(err)
 
@@ -300,7 +300,7 @@ func (s *DKGTSIGProtocolTestSuite) TestComplaint() {
 	round := uint64(1)
 	_, pubKeys, err := test.NewKeys(5)
 	s.Require().NoError(err)
-	gov, err := test.NewGovernance(test.NewState(
+	gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
 		pubKeys, 100, &common.NullLogger{}, true), ConfigRoundShift)
 	s.Require().NoError(err)
 
@@ -365,7 +365,7 @@ func (s *DKGTSIGProtocolTestSuite) TestDuplicateComplaint() {
 	round := uint64(1)
 	_, pubKeys, err := test.NewKeys(5)
 	s.Require().NoError(err)
-	gov, err := test.NewGovernance(test.NewState(
+	gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
 		pubKeys, 100, &common.NullLogger{}, true), ConfigRoundShift)
 	s.Require().NoError(err)
 
@@ -408,7 +408,7 @@ func (s *DKGTSIGProtocolTestSuite) TestAntiComplaint() {
 	round := uint64(1)
 	_, pubKeys, err := test.NewKeys(5)
 	s.Require().NoError(err)
-	gov, err := test.NewGovernance(test.NewState(
+	gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
 		pubKeys, 100, &common.NullLogger{}, true), ConfigRoundShift)
 	s.Require().NoError(err)
 
@@ -466,7 +466,7 @@ func (s *DKGTSIGProtocolTestSuite) TestEncorceNackComplaint() {
 	round := uint64(1)
 	_, pubKeys, err := test.NewKeys(5)
 	s.Require().NoError(err)
-	gov, err := test.NewGovernance(test.NewState(
+	gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
 		pubKeys, 100, &common.NullLogger{}, true), ConfigRoundShift)
 	s.Require().NoError(err)
 
@@ -521,7 +521,7 @@ func (s *DKGTSIGProtocolTestSuite) TestQualifyIDs() {
 	round := uint64(1)
 	_, pubKeys, err := test.NewKeys(5)
 	s.Require().NoError(err)
-	gov, err := test.NewGovernance(test.NewState(
+	gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
 		pubKeys, 100, &common.NullLogger{}, true), ConfigRoundShift)
 	s.Require().NoError(err)
 
@@ -587,7 +587,7 @@ func (s *DKGTSIGProtocolTestSuite) TestPartialSignature() {
 	round := uint64(1)
 	_, pubKeys, err := test.NewKeys(5)
 	s.Require().NoError(err)
-	gov, err := test.NewGovernance(test.NewState(
+	gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
 		pubKeys, 100, &common.NullLogger{}, true), ConfigRoundShift)
 	s.Require().NoError(err)
 
@@ -724,7 +724,7 @@ func (s *DKGTSIGProtocolTestSuite) TestTSigVerifierCache() {
 	n := 10
 	_, pubKeys, err := test.NewKeys(n)
 	s.Require().NoError(err)
-	gov, err := test.NewGovernance(test.NewState(
+	gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
 		pubKeys, 100, &common.NullLogger{}, true), ConfigRoundShift)
 	s.Require().NoError(err)
 	gov.CatchUpWithRound(10)
diff --git a/core/syncer/agreement_test.go b/core/syncer/agreement_test.go
index 4e66f8b..0a12b3c 100644
--- a/core/syncer/agreement_test.go
+++ b/core/syncer/agreement_test.go
@@ -78,13 +78,13 @@ func (s *AgreementTestSuite) TestFutureAgreementResult() {
 		pos         = types.Position{Round: 7, Height: 1000}
 	)
 	gov, err := test.NewGovernance(
-		test.NewState(s.pubKeys, time.Second, &common.NullLogger{}, true),
+		test.NewState(1, s.pubKeys, time.Second, &common.NullLogger{}, true),
 		core.ConfigRoundShift,
 	)
 	s.Require().NoError(err)
 	// Make sure goverance is ready for some future round, including CRS.
 	gov.CatchUpWithRound(futureRound)
-	for i := uint64(1); i <= futureRound; i++ {
+	for i := uint64(2); i <= futureRound; i++ {
 		gov.ProposeCRS(i, common.NewRandomHash().Bytes())
 	}
 	s.Require().NoError(err)
diff --git a/core/test/governance_test.go b/core/test/governance_test.go
index e0a2365..af2b5c5 100644
--- a/core/test/governance_test.go
+++ b/core/test/governance_test.go
@@ -35,11 +35,11 @@ func (s *GovernanceTestSuite) TestEqual() {
 	_, genesisNodes, err := NewKeys(20)
 	req.NoError(err)
 	g1, err := NewGovernance(NewState(
-		genesisNodes, 100*time.Millisecond, &common.NullLogger{}, true), 2)
+		1, genesisNodes, 100*time.Millisecond, &common.NullLogger{}, true), 2)
 	req.NoError(err)
 	// Create a governance with different lambda.
 	g2, err := NewGovernance(NewState(
-		genesisNodes, 50*time.Millisecond, &common.NullLogger{}, true), 2)
+		1, genesisNodes, 50*time.Millisecond, &common.NullLogger{}, true), 2)
 	req.NoError(err)
 	req.False(g1.Equal(g2, true))
 	// Create configs for 3 rounds for g1.
@@ -72,7 +72,7 @@ func (s *GovernanceTestSuite) TestRegisterChange() {
 	_, genesisNodes, err := NewKeys(20)
 	req.NoError(err)
 	g, err := NewGovernance(NewState(
-		genesisNodes, 100*time.Millisecond, &common.NullLogger{}, true), 2)
+		1, genesisNodes, 100*time.Millisecond, &common.NullLogger{}, true), 2)
 	req.NoError(err)
 	// Unable to register change for genesis round.
 	req.Error(g.RegisterConfigChange(0, StateChangeDKGSetSize, uint32(32)))
diff --git a/core/test/network_test.go b/core/test/network_test.go
index 22c31a8..3e9b557 100644
--- a/core/test/network_test.go
+++ b/core/test/network_test.go
@@ -248,7 +248,7 @@ func (s *NetworkTestSuite) TestBroadcastToSet() {
 	_, pubKeys, err := NewKeys(peerCount)
 	req.NoError(err)
 	gov, err := NewGovernance(NewState(
-		pubKeys, time.Second, &common.NullLogger{}, true), 2)
+		1, pubKeys, time.Second, &common.NullLogger{}, true), 2)
 	req.NoError(err)
 	req.NoError(gov.State().RequestChange(StateChangeDKGSetSize, uint32(1)))
 	req.NoError(gov.State().RequestChange(StateChangeNotarySetSize, uint32(1)))
diff --git a/core/test/state.go b/core/test/state.go
index f1cf365..fbf4505 100644
--- a/core/test/state.go
+++ b/core/test/state.go
@@ -117,6 +117,7 @@ type State struct {
 //  - node set
 //  - crs
 func NewState(
+	dkgDelayRound uint64,
 	nodePubKeys []crypto.PublicKey,
 	lambda time.Duration,
 	logger common.Logger,
@@ -126,6 +127,11 @@ func NewState(
 		nodes[types.NewNodeID(key)] = key
 	}
 	genesisCRS := crypto.Keccak256Hash([]byte("__ DEXON"))
+	crs := make([]common.Hash, dkgDelayRound+1)
+	for i := range crs {
+		crs[i] = genesisCRS
+		genesisCRS = crypto.Keccak256Hash(genesisCRS[:])
+	}
 	return &State{
 		local:            local,
 		logger:           logger,
@@ -133,7 +139,7 @@ func NewState(
 		lambdaDKG:        lambda * 10,
 		roundInterval:    1000,
 		minBlockInterval: 4 * lambda,
-		crs:              []common.Hash{genesisCRS},
+		crs:              crs,
 		nodes:            nodes,
 		notarySetSize:    uint32(len(nodes)),
 		dkgSetSize:       uint32(len(nodes)),
diff --git a/core/test/state_test.go b/core/test/state_test.go
index ad3a1d6..8d2b2a2 100644
--- a/core/test/state_test.go
+++ b/core/test/state_test.go
@@ -160,10 +160,10 @@ func (s *StateTestSuite) TestEqual() {
 	)
 	_, genesisNodes, err := NewKeys(20)
 	req.NoError(err)
-	st := NewState(genesisNodes, lambda, &common.NullLogger{}, true)
+	st := NewState(1, genesisNodes, lambda, &common.NullLogger{}, true)
 	req.NoError(st.Equal(st))
 	// One node is missing.
-	st1 := NewState(genesisNodes, lambda, &common.NullLogger{}, true)
+	st1 := NewState(1, genesisNodes, lambda, &common.NullLogger{}, true)
 	for nID := range st1.nodes {
 		delete(st1.nodes, nID)
 		break
@@ -174,7 +174,6 @@ func (s *StateTestSuite) TestEqual() {
 	req.NoError(st.Equal(st2))
 	s.makeConfigChanges(st)
 	req.Equal(st.Equal(st2), ErrStateConfigNotEqual)
-	req.NoError(st.ProposeCRS(1, common.NewRandomHash()))
 	req.NoError(st.ProposeCRS(2, common.NewRandomHash()))
 	req.NoError(st.RequestChange(StateResetDKG, common.NewRandomHash()))
 	masterPubKey := s.newDKGMasterPublicKey(2)
@@ -230,12 +229,12 @@ func (s *StateTestSuite) TestPendingChangesEqual() {
 	// Setup a non-local mode State instance.
 	_, genesisNodes, err := NewKeys(20)
 	req.NoError(err)
-	st := NewState(genesisNodes, lambda, &common.NullLogger{}, false)
+	st := NewState(1, genesisNodes, lambda, &common.NullLogger{}, false)
 	req.NoError(st.Equal(st))
 	// Apply some changes.
 	s.makeConfigChanges(st)
 	crs := common.NewRandomHash()
-	req.NoError(st.ProposeCRS(1, crs))
+	req.NoError(st.ProposeCRS(2, crs))
 	masterPubKey := s.newDKGMasterPublicKey(2)
 	ready := s.newDKGMPKReady(2)
 	comp := s.newDKGComplaint(2)
@@ -251,7 +250,7 @@ func (s *StateTestSuite) TestLocalMode() {
 	)
 	_, genesisNodes, err := NewKeys(20)
 	req.NoError(err)
-	st := NewState(genesisNodes, lambda, &common.NullLogger{}, true)
+	st := NewState(1, genesisNodes, lambda, &common.NullLogger{}, true)
 	config1, nodes1 := st.Snapshot()
 	req.True(s.compareNodes(genesisNodes, nodes1))
 	// Check settings of config1 affected by genesisNodes and lambda.
@@ -274,9 +273,6 @@ func (s *StateTestSuite) TestLocalMode() {
 	req.True(s.findNode(newNodes, pubKey))
 	// Test adding CRS.
 	crs := common.NewRandomHash()
-	req.NoError(st.ProposeCRS(1, crs))
-	req.Equal(st.CRS(1), crs)
-	crs = common.NewRandomHash()
 	req.NoError(st.ProposeCRS(2, crs))
 	req.Equal(st.CRS(2), crs)
 	// Test adding node set, DKG complaints, final, master public key.
@@ -335,16 +331,11 @@ func (s *StateTestSuite) TestPacking() {
 	// Make config changes.
 	_, genesisNodes, err := NewKeys(20)
 	req.NoError(err)
-	st := NewState(genesisNodes, lambda, &common.NullLogger{}, false)
+	st := NewState(1, genesisNodes, lambda, &common.NullLogger{}, false)
 	s.makeConfigChanges(st)
 	// Add new CRS.
 	crs := common.NewRandomHash()
-	req.NoError(st.ProposeCRS(1, crs))
-	packAndApply(st)
-	// Check if CRS is added.
-	req.Equal(st.CRS(1), crs)
-	crs2 := common.NewRandomHash()
-	req.NoError(st.ProposeCRS(2, crs2))
+	req.NoError(st.ProposeCRS(2, crs))
 	// Add new node.
 	prvKey, err := ecdsa.NewPrivateKey()
 	req.NoError(err)
@@ -366,7 +357,7 @@ func (s *StateTestSuite) TestPacking() {
 	config, nodes := st.Snapshot()
 	s.checkConfigChanges(config)
 	// Check if CRS is added.
-	req.Equal(st.CRS(2), crs2)
+	req.Equal(st.CRS(2), crs)
 	// Check if new node is added.
 	req.True(s.findNode(nodes, pubKey))
 	// Check DKGMasterPublicKeys.
@@ -409,14 +400,14 @@ func (s *StateTestSuite) TestRequestBroadcastAndPack() {
 	)
 	_, genesisNodes, err := NewKeys(20)
 	req.NoError(err)
-	st := NewState(genesisNodes, lambda, &common.NullLogger{}, false)
-	st1 := NewState(genesisNodes, lambda, &common.NullLogger{}, false)
+	st := NewState(1, genesisNodes, lambda, &common.NullLogger{}, false)
+	st1 := NewState(1, genesisNodes, lambda, &common.NullLogger{}, false)
 	req.NoError(st.Equal(st1))
 	// Make configuration changes.
 	s.makeConfigChanges(st)
 	// Add new CRS.
 	crs := common.NewRandomHash()
-	req.NoError(st.ProposeCRS(1, crs))
+	req.NoError(st.ProposeCRS(2, crs))
 	// Add new node.
 	prvKey, err := ecdsa.NewPrivateKey()
 	req.NoError(err)
diff --git a/core/utils/nodeset-cache.go b/core/utils/nodeset-cache.go
index 0e616e4..6249665 100644
--- a/core/utils/nodeset-cache.go
+++ b/core/utils/nodeset-cache.go
@@ -223,13 +223,15 @@ func (cache *NodeSetCache) update(round uint64) (nIDs *sets, err error) {
 		return
 	}
 	nIDs = &sets{
-		crs:       crs,
-		nodeSet:   nodeSet,
-		notarySet: make(map[types.NodeID]struct{}),
-		dkgSet: nodeSet.GetSubSet(
-			int(cfg.DKGSetSize), types.NewDKGSetTarget(crs)),
+		crs:        crs,
+		nodeSet:    nodeSet,
+		notarySet:  make(map[types.NodeID]struct{}),
 		leaderNode: make(map[uint64]types.NodeID, cfg.RoundLength),
 	}
+	if round >= dkgDelayRound {
+		nIDs.dkgSet = nodeSet.GetSubSet(
+			int(cfg.DKGSetSize), types.NewDKGSetTarget(crs))
+	}
 	nIDs.notarySet = nodeSet.GetSubSet(
 		int(cfg.NotarySetSize), types.NewNotarySetTarget(crs))
 	cache.rounds[round] = nIDs
diff --git a/core/utils/utils.go b/core/utils/utils.go
index 8486d28..203f57f 100644
--- a/core/utils/utils.go
+++ b/core/utils/utils.go
@@ -26,6 +26,13 @@ import (
 	typesDKG "github.com/dexon-foundation/dexon-consensus/core/types/dkg"
 )
 
+var dkgDelayRound uint64
+
+// SetDKGDelayRound sets the variable.
+func SetDKGDelayRound(delay uint64) {
+	dkgDelayRound = delay
+}
+
 type configAccessor interface {
 	Configuration(round uint64) *types.Config
 }
diff --git a/core/utils_test.go b/core/utils_test.go
index c53a38f..560e923 100644
--- a/core/utils_test.go
+++ b/core/utils_test.go
@@ -48,7 +48,7 @@ func (s *UtilsTestSuite) TestRemoveFromSortedUint32Slice() {
 func (s *UtilsTestSuite) TestVerifyAgreementResult() {
 	prvKeys, pubKeys, err := test.NewKeys(4)
 	s.Require().NoError(err)
-	gov, err := test.NewGovernance(test.NewState(
+	gov, err := test.NewGovernance(test.NewState(DKGDelayRound,
 		pubKeys, time.Second, &common.NullLogger{}, true), ConfigRoundShift)
 	s.Require().NoError(err)
 	cache := utils.NewNodeSetCache(gov)
diff --git a/integration_test/byzantine_test.go b/integration_test/byzantine_test.go
index 1e5a2a9..c90c9a1 100644
--- a/integration_test/byzantine_test.go
+++ b/integration_test/byzantine_test.go
@@ -139,7 +139,7 @@ func (s *ByzantineTestSuite) TestOneSlowNodeOneDeadNode() {
 	// run faster.
 	lambda := 100 * time.Millisecond
 	seedGov, err := test.NewGovernance(
-		test.NewState(
+		test.NewState(core.DKGDelayRound,
 			pubKeys, lambda, &common.NullLogger{}, true),
 		core.ConfigRoundShift)
 	req.NoError(err)
diff --git a/integration_test/consensus_test.go b/integration_test/consensus_test.go
index b469859..4f916c3 100644
--- a/integration_test/consensus_test.go
+++ b/integration_test/consensus_test.go
@@ -210,7 +210,7 @@ func (s *ConsensusTestSuite) TestSimple() {
 	// Setup seed governance instance. Give a short latency to make this test
 	// run faster.
 	seedGov, err := test.NewGovernance(
-		test.NewState(
+		test.NewState(core.DKGDelayRound,
 			pubKeys, 100*time.Millisecond, &common.NullLogger{}, true),
 		core.ConfigRoundShift)
 	req.NoError(err)
@@ -255,7 +255,7 @@ func (s *ConsensusTestSuite) TestSetSizeChange() {
 	req.NoError(err)
 	// Setup seed governance instance.
 	seedGov, err := test.NewGovernance(
-		test.NewState(pubKeys, 100*time.Millisecond, &common.NullLogger{}, true),
+		test.NewState(core.DKGDelayRound, pubKeys, 100*time.Millisecond, &common.NullLogger{}, true),
 		core.ConfigRoundShift)
 	req.NoError(err)
 	req.NoError(seedGov.State().RequestChange(
@@ -350,7 +350,7 @@ func (s *ConsensusTestSuite) TestSync() {
 	// Setup seed governance instance. Give a short latency to make this test
 	// run faster.
 	seedGov, err := test.NewGovernance(
-		test.NewState(
+		test.NewState(core.DKGDelayRound,
 			pubKeys, 100*time.Millisecond, &common.NullLogger{}, true),
 		core.ConfigRoundShift)
 	req.NoError(err)
diff --git a/simulation/node.go b/simulation/node.go
index 758f980..fc5be90 100644
--- a/simulation/node.go
+++ b/simulation/node.go
@@ -90,7 +90,7 @@ func newNode(prvKey crypto.PrivateKey, logger common.Logger,
 	}
 	// Sync config to state in governance.
 	gov, err := test.NewGovernance(
-		test.NewState(
+		test.NewState(core.DKGDelayRound,
 			[]crypto.PublicKey{pubKey}, time.Millisecond, logger, true),
 		core.ConfigRoundShift)
 	if err != nil {