consensus: dexcon: disqualify dead node (#280)

Since a qualified node might fail stopped, we need to remove them from
qualified nodes to maintain network integrity. We do this by inspect the
previous round to see if there are dead nodes. A dead node is a notary
set node that does not propose any block in the previous round. We
disqualify them by fining them so their staked value is 1 wei below
minStake. This make them unqualified for being notary set in the follow
on rounds.

11 files changed, 294 insertions, 152 deletions

diff --git a/consensus/dexcon/dexcon.go b/consensus/dexcon/dexcon.go
index c837e3a43..3e520438b 100644
--- a/consensus/dexcon/dexcon.go
+++ b/consensus/dexcon/dexcon.go
@@ -17,6 +17,8 @@
 package dexcon
 
 import (
+	"encoding/hex"
+	"fmt"
 	"math/big"
 
 	"github.com/dexon-foundation/dexon/common"
@@ -24,11 +26,13 @@ import (
 	"github.com/dexon-foundation/dexon/core/state"
 	"github.com/dexon-foundation/dexon/core/types"
 	"github.com/dexon-foundation/dexon/core/vm"
+	"github.com/dexon-foundation/dexon/log"
 	"github.com/dexon-foundation/dexon/rpc"
 )
 
 type GovernanceStateFetcher interface {
 	GetStateForConfigAtRound(round uint64) *vm.GovernanceState
+	NotarySetNodeKeyAddresses(round uint64) (map[common.Address]struct{}, error)
 }
 
 // Dexcon is a delegated proof-of-stake consensus engine.
@@ -137,8 +141,39 @@ func (d *Dexcon) Finalize(chain consensus.ChainReader, header *types.Header, sta
 	gs := vm.GovernanceState{state}
 
 	height := gs.RoundHeight(new(big.Int).SetUint64(header.Round))
+
+	// The first block of a round is found.
 	if header.Round > 0 && height.Uint64() == 0 {
 		gs.PushRoundHeight(header.Number)
+
+		// Check for dead node and disqualify them.
+		// A dead node node is defined as: a notary set node that did not propose
+		// any block in the past round.
+		addrs, err := d.govStateFetcer.NotarySetNodeKeyAddresses(header.Round - 1)
+		if err != nil {
+			panic(err)
+		}
+
+		gcs := d.govStateFetcer.GetStateForConfigAtRound(header.Round - 1)
+
+		for addr := range addrs {
+			offset := gcs.NodesOffsetByNodeKeyAddress(addr)
+			if offset.Cmp(big.NewInt(0)) < 0 {
+				panic(fmt.Errorf("invalid notary set found, addr = %s", addr.String()))
+			}
+
+			node := gcs.Node(offset)
+			lastHeight := gs.LastProposedHeight(node.Owner)
+			prevRoundHeight := gs.RoundHeight(big.NewInt(int64(header.Round - 1)))
+
+			if lastHeight.Uint64() < prevRoundHeight.Uint64() {
+				log.Info("Disqualify node", "round", header.Round, "nodePubKey", hex.EncodeToString(node.PublicKey))
+				err = gs.Disqualify(node)
+				if err != nil {
+					log.Error("Failed to disqualify node", "err", err)
+				}
+			}
+		}
 	}
 
 	// Distribute block reward and halving condition.
@@ -147,16 +182,17 @@ func (d *Dexcon) Finalize(chain consensus.ChainReader, header *types.Header, sta
 	} else {
 		reward := d.calculateBlockReward(int64(header.Round), state)
 		state.AddBalance(header.Coinbase, reward)
-
+		header.Reward = reward
 		gs.IncTotalSupply(reward)
 
-		config := gs.Configuration()
+		// Record last proposed height.
+		gs.PutLastProposedHeight(header.Coinbase, header.Number)
 
 		// Check if halving checkpoint reached.
+		config := gs.Configuration()
 		if gs.TotalSupply().Cmp(config.NextHalvingSupply) >= 0 {
 			gs.MiningHalved()
 		}
-		header.Reward = reward
 	}
 
 	header.Root = state.IntermediateRoot(true)
diff --git a/consensus/dexcon/dexcon_test.go b/consensus/dexcon/dexcon_test.go
index f34823570..0181a80f3 100644
--- a/consensus/dexcon/dexcon_test.go
+++ b/consensus/dexcon/dexcon_test.go
@@ -31,14 +31,18 @@ import (
 	"github.com/dexon-foundation/dexon/params"
 )
 
-type GovStateFetcher struct {
+type govStateFetcher struct {
 	statedb *state.StateDB
 }
 
-func (g *GovStateFetcher) GetStateForConfigAtRound(_ uint64) *vm.GovernanceState {
+func (g *govStateFetcher) GetStateForConfigAtRound(_ uint64) *vm.GovernanceState {
 	return &vm.GovernanceState{g.statedb}
 }
 
+func (g *govStateFetcher) NotarySetNodeKeyAddresses(round uint64) (map[common.Address]struct{}, error) {
+	return make(map[common.Address]struct{}), nil
+}
+
 type DexconTestSuite struct {
 	suite.Suite
 
@@ -86,7 +90,7 @@ func (d *DexconTestSuite) SetupTest() {
 
 func (d *DexconTestSuite) TestBlockRewardCalculation() {
 	consensus := New()
-	consensus.SetGovStateFetcher(&GovStateFetcher{d.stateDB})
+	consensus.SetGovStateFetcher(&govStateFetcher{d.stateDB})
 
 	d.s.IncTotalStaked(big.NewInt(1e18))
 
diff --git a/core/governance.go b/core/governance.go
index da310a1cd..bb49efb53 100644
--- a/core/governance.go
+++ b/core/governance.go
@@ -1,16 +1,22 @@
 package core
 
 import (
+	"encoding/hex"
 	"fmt"
 	"math/big"
 	"time"
 
+	coreCommon "github.com/dexon-foundation/dexon-consensus/common"
 	dexCore "github.com/dexon-foundation/dexon-consensus/core"
+	coreCrypto "github.com/dexon-foundation/dexon-consensus/core/crypto"
+	coreEcdsa "github.com/dexon-foundation/dexon-consensus/core/crypto/ecdsa"
 	coreTypes "github.com/dexon-foundation/dexon-consensus/core/types"
 	dkgTypes "github.com/dexon-foundation/dexon-consensus/core/types/dkg"
 
+	"github.com/dexon-foundation/dexon/common"
 	"github.com/dexon-foundation/dexon/core/state"
 	"github.com/dexon-foundation/dexon/core/vm"
+	"github.com/dexon-foundation/dexon/crypto"
 	"github.com/dexon-foundation/dexon/log"
 	"github.com/dexon-foundation/dexon/rlp"
 )
@@ -41,11 +47,14 @@ func (g *governanceStateDB) StateAt(height uint64) (*state.StateDB, error) {
 }
 
 type Governance struct {
-	db GovernanceStateDB
+	db           GovernanceStateDB
+	nodeSetCache *dexCore.NodeSetCache
 }
 
 func NewGovernance(db GovernanceStateDB) *Governance {
-	return &Governance{db: db}
+	g := &Governance{db: db}
+	g.nodeSetCache = dexCore.NewNodeSetCache(g)
+	return g
 }
 
 func (g *Governance) GetHeadState() *vm.GovernanceState {
@@ -93,6 +102,43 @@ func (g *Governance) GetStateAtRound(round uint64) *vm.GovernanceState {
 	return &vm.GovernanceState{StateDB: s}
 }
 
+func (g *Governance) GetStateForDKGAtRound(round uint64) *vm.GovernanceState {
+	dkgRound := g.GetHeadState().DKGRound().Uint64()
+	if round > dkgRound {
+		return nil
+	}
+	if round == dkgRound {
+		return g.GetHeadState()
+	}
+	return g.GetStateAtRound(round)
+}
+
+func (d *Governance) CRSRound() uint64 {
+	return d.GetHeadState().CRSRound().Uint64()
+}
+
+// CRS returns the CRS for a given round.
+func (d *Governance) CRS(round uint64) coreCommon.Hash {
+	if round <= dexCore.DKGDelayRound {
+		s := d.GetStateAtRound(0)
+		crs := s.CRS()
+		for i := uint64(0); i < round; i++ {
+			crs = crypto.Keccak256Hash(crs[:])
+		}
+		return coreCommon.Hash(crs)
+	}
+	if round > d.CRSRound() {
+		return coreCommon.Hash{}
+	}
+	var s *vm.GovernanceState
+	if round == d.CRSRound() {
+		s = d.GetHeadState()
+	} else {
+		s = d.GetStateAtRound(round)
+	}
+	return coreCommon.Hash(s.CRS())
+}
+
 func (g *Governance) Configuration(round uint64) *coreTypes.Config {
 	configHelper := g.GetStateForConfigAtRound(round)
 	c := configHelper.Configuration()
@@ -110,15 +156,62 @@ func (g *Governance) GetRoundHeight(round uint64) uint64 {
 	return g.GetHeadState().RoundHeight(big.NewInt(int64(round))).Uint64()
 }
 
-func (g *Governance) GetStateForDKGAtRound(round uint64) *vm.GovernanceState {
-	dkgRound := g.GetHeadState().DKGRound().Uint64()
-	if round > dkgRound {
-		return nil
+// NodeSet returns the current node set.
+func (d *Governance) NodeSet(round uint64) []coreCrypto.PublicKey {
+	s := d.GetStateForConfigAtRound(round)
+	var pks []coreCrypto.PublicKey
+
+	for _, n := range s.QualifiedNodes() {
+		pk, err := coreEcdsa.NewPublicKeyFromByteSlice(n.PublicKey)
+		if err != nil {
+			panic(err)
+		}
+		pks = append(pks, pk)
 	}
-	if round == dkgRound {
-		return g.GetHeadState()
+	return pks
+}
+
+func (d *Governance) NotarySet(round uint64) (map[string]struct{}, error) {
+	notarySet, err := d.nodeSetCache.GetNotarySet(round)
+	if err != nil {
+		return nil, err
 	}
-	return g.GetStateAtRound(round)
+
+	r := make(map[string]struct{}, len(notarySet))
+	for id := range notarySet {
+		if key, exists := d.nodeSetCache.GetPublicKey(id); exists {
+			r[hex.EncodeToString(key.Bytes())] = struct{}{}
+		}
+	}
+	return r, nil
+}
+
+func (d *Governance) NotarySetNodeKeyAddresses(round uint64) (map[common.Address]struct{}, error) {
+	notarySet, err := d.nodeSetCache.GetNotarySet(round)
+	if err != nil {
+		return nil, err
+	}
+
+	r := make(map[common.Address]struct{}, len(notarySet))
+	for id := range notarySet {
+		r[vm.IdToAddress(id)] = struct{}{}
+	}
+	return r, nil
+}
+
+func (d *Governance) DKGSet(round uint64) (map[string]struct{}, error) {
+	dkgSet, err := d.nodeSetCache.GetDKGSet(round)
+	if err != nil {
+		return nil, err
+	}
+
+	r := make(map[string]struct{}, len(dkgSet))
+	for id := range dkgSet {
+		if key, exists := d.nodeSetCache.GetPublicKey(id); exists {
+			r[hex.EncodeToString(key.Bytes())] = struct{}{}
+		}
+	}
+	return r, nil
 }
 
 func (g *Governance) DKGComplaints(round uint64) []*dkgTypes.Complaint {
diff --git a/core/vm/oracle_contract_abi.go b/core/vm/oracle_contract_abi.go
index f0845eb7b..cd037b068 100644
--- a/core/vm/oracle_contract_abi.go
+++ b/core/vm/oracle_contract_abi.go
@@ -130,7 +130,7 @@ const GovernanceABIJSON = `
         "type": "uint256"
       },
       {
-        "name": "unstaked_at",
+        "name": "unstakedAt",
         "type": "uint256"
       }
     ],
@@ -530,6 +530,25 @@ const GovernanceABIJSON = `
   },
   {
     "constant": true,
+    "inputs": [
+      {
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "name": "lastProposedHeight",
+    "outputs": [
+      {
+        "name": "",
+        "type": "uint256"
+      }
+    ],
+    "payable": false,
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "constant": true,
     "inputs": [],
     "name": "minGasPrice",
     "outputs": [
diff --git a/core/vm/oracle_contracts.go b/core/vm/oracle_contracts.go
index c138a6b4a..ac6d7315c 100644
--- a/core/vm/oracle_contracts.go
+++ b/core/vm/oracle_contracts.go
@@ -62,6 +62,7 @@ const (
 	nodesLoc
 	nodesOffsetByAddressLoc
 	nodesOffsetByNodeKeyAddressLoc
+	lastProposedHeightLoc
 	crsRoundLoc
 	crsLoc
 	dkgRoundLoc
@@ -332,7 +333,8 @@ func (s *GovernanceState) DecTotalStaked(amount *big.Int) {
 //     string location;
 //     string url;
 //     uint256 unstaked;
-//     uint256 unstaked_at;
+//     uint256 unstakedAt;
+//     uint256 lastProposedHeight;
 // }
 //
 // Node[] nodes;
@@ -543,6 +545,16 @@ func (s *GovernanceState) GetNodeByID(id coreTypes.NodeID) (*nodeInfo, error) {
 	return node, nil
 }
 
+// mapping(address => uint256) public lastProposedHeight;
+func (s *GovernanceState) LastProposedHeight(addr common.Address) *big.Int {
+	loc := s.getMapLoc(big.NewInt(lastProposedHeightLoc), addr.Bytes())
+	return s.getStateBigInt(loc)
+}
+func (s *GovernanceState) PutLastProposedHeight(addr common.Address, height *big.Int) {
+	loc := s.getMapLoc(big.NewInt(lastProposedHeightLoc), addr.Bytes())
+	s.setStateBigInt(loc, height)
+}
+
 // uint256 public crsRound;
 func (s *GovernanceState) CRSRound() *big.Int {
 	return s.getStateBigInt(big.NewInt(crsRoundLoc))
@@ -960,6 +972,31 @@ func (s *GovernanceState) Register(
 	s.IncTotalStaked(staked)
 }
 
+func (s *GovernanceState) Disqualify(n *nodeInfo) error {
+	nodeAddr, err := publicKeyToNodeKeyAddress(n.PublicKey)
+	if err != nil {
+		return err
+	}
+
+	// Node might already been unstaked in the latest state.
+	offset := s.NodesOffsetByNodeKeyAddress(nodeAddr)
+	if offset.Cmp(big.NewInt(0)) < 0 {
+		return errors.New("node does not exist")
+	}
+
+	// Fine the node so it's staked value is 1 wei under minStake.
+	node := s.Node(offset)
+	extra := new(big.Int).Sub(new(big.Int).Sub(node.Staked, node.Fined), s.MinStake())
+	amount := new(big.Int).Add(extra, big.NewInt(1))
+
+	if amount.Cmp(big.NewInt(0)) > 0 {
+		node.Fined = new(big.Int).Add(node.Fined, amount)
+		s.UpdateNode(offset, node)
+	}
+
+	return nil
+}
+
 const decimalMultiplier = 100000000.0
 
 // Configuration returns the current configuration.
@@ -2248,6 +2285,16 @@ func (g *GovernanceContract) Run(evm *EVM, input []byte, contract *Contract) (re
 			return nil, errExecutionReverted
 		}
 		return res, nil
+	case "lastProposedHeight":
+		address := common.Address{}
+		if err := method.Inputs.Unpack(&address, arguments); err != nil {
+			return nil, errExecutionReverted
+		}
+		res, err := method.Outputs.Pack(g.state.LastProposedHeight(address))
+		if err != nil {
+			return nil, errExecutionReverted
+		}
+		return res, nil
 	case "lockupPeriod":
 		res, err := method.Outputs.Pack(g.state.LockupPeriod())
 		if err != nil {
diff --git a/core/vm/oracle_contracts_test.go b/core/vm/oracle_contracts_test.go
index 4b25b39da..55876f9b2 100644
--- a/core/vm/oracle_contracts_test.go
+++ b/core/vm/oracle_contracts_test.go
@@ -59,10 +59,22 @@ func randomBytes(minLength, maxLength int32) []byte {
 	return b
 }
 
+func newPrefundAccount(s *state.StateDB) (*ecdsa.PrivateKey, common.Address) {
+	privKey, err := crypto.GenerateKey()
+	if err != nil {
+		panic(err)
+	}
+	address := crypto.PubkeyToAddress(privKey.PublicKey)
+
+	s.AddBalance(address, new(big.Int).Mul(big.NewInt(1e18), big.NewInt(2e6)))
+	return privKey, address
+}
+
 type GovernanceStateTestSuite struct {
 	suite.Suite
 
-	s *GovernanceState
+	stateDB *state.StateDB
+	s       *GovernanceState
 }
 
 func (g *GovernanceStateTestSuite) SetupTest() {
@@ -71,7 +83,13 @@ func (g *GovernanceStateTestSuite) SetupTest() {
 	if err != nil {
 		panic(err)
 	}
+	g.stateDB = statedb
 	g.s = &GovernanceState{statedb}
+
+	config := params.TestnetChainConfig.Dexcon
+	g.s.Initialize(config, new(big.Int).Mul(big.NewInt(1e18), big.NewInt(1e7)))
+
+	statedb.Commit(true)
 }
 
 func (g *GovernanceStateTestSuite) TestReadWriteEraseBytes() {
@@ -117,6 +135,31 @@ func (g *GovernanceStateTestSuite) TestReadWriteErase1DArray() {
 	}
 }
 
+func (g *GovernanceStateTestSuite) TestDisqualify() {
+	privKey, addr := newPrefundAccount(g.stateDB)
+	pk := crypto.FromECDSAPub(&privKey.PublicKey)
+
+	g.s.Register(addr, pk, "Test", "test@dexon.org", "Taipei", "https://test.com", g.s.MinStake())
+
+	node := g.s.Node(big.NewInt(0))
+	g.Require().Equal(uint64(0), node.Fined.Uint64())
+
+	// Disqualify
+	g.s.Disqualify(node)
+	node = g.s.Node(big.NewInt(0))
+	g.Require().Equal(uint64(1), node.Fined.Uint64())
+
+	// Disqualify again should change nothing.
+	g.s.Disqualify(node)
+	node = g.s.Node(big.NewInt(0))
+	g.Require().Equal(uint64(1), node.Fined.Uint64())
+
+	// Disqualify none exist node should return error.
+	privKey2, _ := newPrefundAccount(g.stateDB)
+	node.PublicKey = crypto.FromECDSAPub(&privKey2.PublicKey)
+	g.Require().Error(g.s.Disqualify(node))
+}
+
 func TestGovernanceState(t *testing.T) {
 	suite.Run(t, new(GovernanceStateTestSuite))
 }
@@ -203,17 +246,6 @@ func (g *OracleContractsTestSuite) TearDownTest() {
 	}
 }
 
-func (g *OracleContractsTestSuite) newPrefundAccount() (*ecdsa.PrivateKey, common.Address) {
-	privKey, err := crypto.GenerateKey()
-	if err != nil {
-		panic(err)
-	}
-	address := crypto.PubkeyToAddress(privKey.PublicKey)
-
-	g.stateDB.AddBalance(address, new(big.Int).Mul(big.NewInt(1e18), big.NewInt(2e6)))
-	return privKey, address
-}
-
 func (g *OracleContractsTestSuite) call(
 	contractAddr common.Address, caller common.Address, input []byte, value *big.Int) ([]byte, error) {
 
@@ -225,7 +257,7 @@ func (g *OracleContractsTestSuite) call(
 }
 
 func (g *OracleContractsTestSuite) TestTransferOwnership() {
-	_, addr := g.newPrefundAccount()
+	_, addr := newPrefundAccount(g.stateDB)
 
 	input, err := GovernanceABI.ABI.Pack("transferOwnership", addr)
 	g.Require().NoError(err)
@@ -241,7 +273,7 @@ func (g *OracleContractsTestSuite) TestTransferOwnership() {
 }
 
 func (g *OracleContractsTestSuite) TestTransferNodeOwnership() {
-	privKey, addr := g.newPrefundAccount()
+	privKey, addr := newPrefundAccount(g.stateDB)
 	pk := crypto.FromECDSAPub(&privKey.PublicKey)
 	nodeKeyAddr := crypto.PubkeyToAddress(privKey.PublicKey)
 
@@ -253,14 +285,14 @@ func (g *OracleContractsTestSuite) TestTransferNodeOwnership() {
 
 	offset := g.s.NodesOffsetByAddress(addr)
 
-	_, newAddr := g.newPrefundAccount()
+	_, newAddr := newPrefundAccount(g.stateDB)
 	newNodeKeyAddr := crypto.PubkeyToAddress(privKey.PublicKey)
 
 	input, err = GovernanceABI.ABI.Pack("transferNodeOwnership", newAddr)
 	g.Require().NoError(err)
 
 	// Call with non-owner.
-	_, noneOwner := g.newPrefundAccount()
+	_, noneOwner := newPrefundAccount(g.stateDB)
 	_, err = g.call(GovernanceContractAddress, noneOwner, input, big.NewInt(0))
 	g.Require().Error(err)
 
@@ -273,7 +305,7 @@ func (g *OracleContractsTestSuite) TestTransferNodeOwnership() {
 	g.Require().Equal(offset.Uint64(), g.s.NodesOffsetByNodeKeyAddress(newNodeKeyAddr).Uint64())
 
 	// Call with owner.
-	privKey2, addr2 := g.newPrefundAccount()
+	privKey2, addr2 := newPrefundAccount(g.stateDB)
 	pk2 := crypto.FromECDSAPub(&privKey2.PublicKey)
 	input, err = GovernanceABI.ABI.Pack("register", pk2, "Test2", "test1@dexon.org", "Taipei", "https://dexon.org")
 	g.Require().NoError(err)
@@ -288,7 +320,7 @@ func (g *OracleContractsTestSuite) TestTransferNodeOwnership() {
 }
 
 func (g *OracleContractsTestSuite) TestStakingMechanism() {
-	privKey, addr := g.newPrefundAccount()
+	privKey, addr := newPrefundAccount(g.stateDB)
 	pk := crypto.FromECDSAPub(&privKey.PublicKey)
 
 	// Register with some stake.
@@ -374,7 +406,7 @@ func (g *OracleContractsTestSuite) TestStakingMechanism() {
 	amount = new(big.Int).Mul(big.NewInt(1e18), big.NewInt(1e6))
 
 	// 2nd node Stake.
-	privKey2, addr2 := g.newPrefundAccount()
+	privKey2, addr2 := newPrefundAccount(g.stateDB)
 	pk2 := crypto.FromECDSAPub(&privKey2.PublicKey)
 	input, err = GovernanceABI.ABI.Pack("register", pk2, "Test2", "test2@dexon.org", "Taipei", "https://dexon.org")
 	g.Require().NoError(err)
@@ -440,7 +472,7 @@ func (g *OracleContractsTestSuite) TestStakingMechanism() {
 }
 
 func (g *OracleContractsTestSuite) TestFine() {
-	privKey, addr := g.newPrefundAccount()
+	privKey, addr := newPrefundAccount(g.stateDB)
 	pk := crypto.FromECDSAPub(&privKey.PublicKey)
 
 	// Stake.
@@ -452,7 +484,7 @@ func (g *OracleContractsTestSuite) TestFine() {
 	g.Require().Equal(1, len(g.s.QualifiedNodes()))
 	g.Require().Equal(ownerStaked, g.s.Node(big.NewInt(0)).Staked)
 
-	_, finePayer := g.newPrefundAccount()
+	_, finePayer := newPrefundAccount(g.stateDB)
 	amount := new(big.Int).Mul(big.NewInt(1e18), big.NewInt(5e5))
 
 	// Paying to node without fine should fail.
@@ -497,7 +529,7 @@ func (g *OracleContractsTestSuite) TestFine() {
 }
 
 func (g *OracleContractsTestSuite) TestUpdateConfiguration() {
-	_, addr := g.newPrefundAccount()
+	_, addr := newPrefundAccount(g.stateDB)
 
 	input, err := GovernanceABI.ABI.Pack("updateConfiguration",
 		new(big.Int).Mul(big.NewInt(1e18), big.NewInt(1e6)),
@@ -523,7 +555,7 @@ func (g *OracleContractsTestSuite) TestUpdateConfiguration() {
 }
 
 func (g *OracleContractsTestSuite) TestConfigurationReading() {
-	_, addr := g.newPrefundAccount()
+	_, addr := newPrefundAccount(g.stateDB)
 
 	// CRS.
 	input, err := GovernanceABI.ABI.Pack("crs")
@@ -657,7 +689,7 @@ func (g *OracleContractsTestSuite) TestConfigurationReading() {
 }
 
 func (g *OracleContractsTestSuite) TestReportForkVote() {
-	key, addr := g.newPrefundAccount()
+	key, addr := newPrefundAccount(g.stateDB)
 	pkBytes := crypto.FromECDSAPub(&key.PublicKey)
 
 	// Stake.
@@ -723,7 +755,7 @@ func (g *OracleContractsTestSuite) TestReportForkVote() {
 }
 
 func (g *OracleContractsTestSuite) TestReportForkBlock() {
-	key, addr := g.newPrefundAccount()
+	key, addr := newPrefundAccount(g.stateDB)
 	pkBytes := crypto.FromECDSAPub(&key.PublicKey)
 
 	// Stake.
@@ -800,7 +832,7 @@ func (g *OracleContractsTestSuite) TestReportForkBlock() {
 }
 
 func (g *OracleContractsTestSuite) TestMiscVariableReading() {
-	privKey, addr := g.newPrefundAccount()
+	privKey, addr := newPrefundAccount(g.stateDB)
 	pk := crypto.FromECDSAPub(&privKey.PublicKey)
 
 	input, err := GovernanceABI.ABI.Pack("totalSupply")
@@ -898,7 +930,7 @@ func (v *testTSigVerifierMock) VerifySignature(coreCommon.Hash, coreCrypto.Signa
 
 func (g *OracleContractsTestSuite) TestResetDKG() {
 	for i := uint32(0); i < g.config.DKGSetSize; i++ {
-		privKey, addr := g.newPrefundAccount()
+		privKey, addr := newPrefundAccount(g.stateDB)
 		pk := crypto.FromECDSAPub(&privKey.PublicKey)
 
 		// Stake.
@@ -1033,7 +1065,7 @@ func (g *OracleContractsTestSuite) TestResetDKG() {
 
 		g.context.BlockNumber = big.NewInt(
 			roundHeight*int64(round) + roundHeight*int64(r) + roundHeight*80/100)
-		_, addr := g.newPrefundAccount()
+		_, addr := newPrefundAccount(g.stateDB)
 		newCRS := randomBytes(common.HashLength, common.HashLength)
 		input, err := GovernanceABI.ABI.Pack("resetDKG", newCRS)
 		g.Require().NoError(err)
diff --git a/dex/app_test.go b/dex/app_test.go
index 7b158dd9e..e648abdbd 100644
--- a/dex/app_test.go
+++ b/dex/app_test.go
@@ -2299,12 +2299,10 @@ func newDexon(masterKey *ecdsa.PrivateKey, accountNum int) (*Dexon, []*ecdsa.Pri
 	db := ethdb.NewMemDatabase()
 
 	genesis := core.DefaultTestnetGenesisBlock()
-	genesis.Alloc = core.GenesisAlloc{
-		crypto.PubkeyToAddress(masterKey.PublicKey): {
-			Balance:   big.NewInt(100000000000000000),
-			Staked:    big.NewInt(50000000000000000),
-			PublicKey: crypto.FromECDSAPub(&masterKey.PublicKey),
-		},
+	genesis.Alloc[crypto.PubkeyToAddress(masterKey.PublicKey)] = core.GenesisAccount{
+		Balance:   big.NewInt(100000000000000000),
+		Staked:    big.NewInt(50000000000000000),
+		PublicKey: crypto.FromECDSAPub(&masterKey.PublicKey),
 	}
 
 	var accounts []*ecdsa.PrivateKey
@@ -2322,7 +2320,7 @@ func newDexon(masterKey *ecdsa.PrivateKey, accountNum int) (*Dexon, []*ecdsa.Pri
 	}
 
 	genesis.Config.Dexcon.BlockGasLimit = 2000000
-	genesis.Config.Dexcon.RoundLength = 60
+	genesis.Config.Dexcon.RoundLength = 600
 	genesis.Config.Dexcon.Owner = crypto.PubkeyToAddress(masterKey.PublicKey)
 
 	chainConfig, _, err := core.SetupGenesisBlock(db, genesis)
diff --git a/dex/downloader/testchain_test.go b/dex/downloader/testchain_test.go
index 722159bc0..15528c509 100644
--- a/dex/downloader/testchain_test.go
+++ b/dex/downloader/testchain_test.go
@@ -342,3 +342,7 @@ func (g *govStateFetcher) GetStateForConfigAtRound(round uint64) *vm.GovernanceS
 	}
 	return nil
 }
+
+func (g *govStateFetcher) NotarySetNodeKeyAddresses(round uint64) (map[common.Address]struct{}, error) {
+	return make(map[common.Address]struct{}), nil
+}
diff --git a/dex/governance.go b/dex/governance.go
index c2f2918b1..0d6ca0eba 100644
--- a/dex/governance.go
+++ b/dex/governance.go
@@ -20,13 +20,8 @@ package dex
 import (
 	"context"
 	"crypto/ecdsa"
-	"encoding/hex"
 	"math/big"
 
-	coreCommon "github.com/dexon-foundation/dexon-consensus/common"
-	dexCore "github.com/dexon-foundation/dexon-consensus/core"
-	coreCrypto "github.com/dexon-foundation/dexon-consensus/core/crypto"
-	coreEcdsa "github.com/dexon-foundation/dexon-consensus/core/crypto/ecdsa"
 	coreTypes "github.com/dexon-foundation/dexon-consensus/core/types"
 	dkgTypes "github.com/dexon-foundation/dexon-consensus/core/types/dkg"
 
@@ -42,11 +37,10 @@ import (
 type DexconGovernance struct {
 	*core.Governance
 
-	b            *DexAPIBackend
-	chainConfig  *params.ChainConfig
-	privateKey   *ecdsa.PrivateKey
-	address      common.Address
-	nodeSetCache *dexCore.NodeSetCache
+	b           *DexAPIBackend
+	chainConfig *params.ChainConfig
+	privateKey  *ecdsa.PrivateKey
+	address     common.Address
 }
 
 // NewDexconGovernance returns a governance implementation of the DEXON
@@ -61,7 +55,6 @@ func NewDexconGovernance(backend *DexAPIBackend, chainConfig *params.ChainConfig
 		privateKey:  privKey,
 		address:     crypto.PubkeyToAddress(privKey.PublicKey),
 	}
-	g.nodeSetCache = dexCore.NewNodeSetCache(g)
 	return g
 }
 
@@ -110,36 +103,10 @@ func (d *DexconGovernance) sendGovTx(ctx context.Context, data []byte) error {
 	return d.b.SendTx(ctx, tx)
 }
 
-// CRS returns the CRS for a given round.
-func (d *DexconGovernance) CRS(round uint64) coreCommon.Hash {
-	if round <= dexCore.DKGDelayRound {
-		s := d.GetStateAtRound(0)
-		crs := s.CRS()
-		for i := uint64(0); i < round; i++ {
-			crs = crypto.Keccak256Hash(crs[:])
-		}
-		return coreCommon.Hash(crs)
-	}
-	if round > d.CRSRound() {
-		return coreCommon.Hash{}
-	}
-	var s *vm.GovernanceState
-	if round == d.CRSRound() {
-		s = d.GetHeadState()
-	} else {
-		s = d.GetStateAtRound(round)
-	}
-	return coreCommon.Hash(s.CRS())
-}
-
 func (d *DexconGovernance) Round() uint64 {
 	return d.b.CurrentBlock().Round()
 }
 
-func (d *DexconGovernance) CRSRound() uint64 {
-	return d.GetHeadState().CRSRound().Uint64()
-}
-
 // ProposeCRS send proposals of a new CRS
 func (d *DexconGovernance) ProposeCRS(round uint64, signedCRS []byte) {
 	data, err := vm.PackProposeCRS(round, signedCRS)
@@ -154,21 +121,6 @@ func (d *DexconGovernance) ProposeCRS(round uint64, signedCRS []byte) {
 	}
 }
 
-// NodeSet returns the current node set.
-func (d *DexconGovernance) NodeSet(round uint64) []coreCrypto.PublicKey {
-	s := d.GetStateForConfigAtRound(round)
-	var pks []coreCrypto.PublicKey
-
-	for _, n := range s.QualifiedNodes() {
-		pk, err := coreEcdsa.NewPublicKeyFromByteSlice(n.PublicKey)
-		if err != nil {
-			panic(err)
-		}
-		pks = append(pks, pk)
-	}
-	return pks
-}
-
 // AddDKGComplaint adds a DKGComplaint.
 func (d *DexconGovernance) AddDKGComplaint(round uint64, complaint *dkgTypes.Complaint) {
 	data, err := vm.PackAddDKGComplaint(round, complaint)
@@ -253,49 +205,6 @@ func (d *DexconGovernance) ReportForkBlock(block1, block2 *coreTypes.Block) {
 	}
 }
 
-func (d *DexconGovernance) NotarySet(round uint64) (map[string]struct{}, error) {
-	notarySet, err := d.nodeSetCache.GetNotarySet(round)
-	if err != nil {
-		return nil, err
-	}
-
-	r := make(map[string]struct{}, len(notarySet))
-	for id := range notarySet {
-		if key, exists := d.nodeSetCache.GetPublicKey(id); exists {
-			r[hex.EncodeToString(key.Bytes())] = struct{}{}
-		}
-	}
-	return r, nil
-}
-
-func (d *DexconGovernance) NotarySetAddresses(round uint64) (map[common.Address]struct{}, error) {
-	notarySet, err := d.nodeSetCache.GetNotarySet(round)
-	if err != nil {
-		return nil, err
-	}
-
-	r := make(map[common.Address]struct{}, len(notarySet))
-	for id := range notarySet {
-		r[vm.IdToAddress(id)] = struct{}{}
-	}
-	return r, nil
-}
-
-func (d *DexconGovernance) DKGSet(round uint64) (map[string]struct{}, error) {
-	dkgSet, err := d.nodeSetCache.GetDKGSet(round)
-	if err != nil {
-		return nil, err
-	}
-
-	r := make(map[string]struct{}, len(dkgSet))
-	for id := range dkgSet {
-		if key, exists := d.nodeSetCache.GetPublicKey(id); exists {
-			r[hex.EncodeToString(key.Bytes())] = struct{}{}
-		}
-	}
-	return r, nil
-}
-
 func (d *DexconGovernance) ResetDKG(newSignedCRS []byte) {
 	data, err := vm.PackResetDKG(newSignedCRS)
 	if err != nil {
diff --git a/dex/recovery.go b/dex/recovery.go
index cfc8ae203..0e5c60e1a 100644
--- a/dex/recovery.go
+++ b/dex/recovery.go
@@ -442,7 +442,7 @@ func (r *Recovery) Votes(height uint64) (uint64, error) {
 		return 0, err
 	}
 
-	notarySet, err := r.gov.NotarySetAddresses(r.gov.Round())
+	notarySet, err := r.gov.NotarySetNodeKeyAddresses(r.gov.Round())
 	if err != nil {
 		return 0, err
 	}
diff --git a/params/config.go b/params/config.go
index f61a9b6df..1eb016019 100644
--- a/params/config.go
+++ b/params/config.go
@@ -26,10 +26,10 @@ import (
 
 // Genesis hashes to enforce below configs on.
 var (
-	MainnetGenesisHash = common.HexToHash("0x8ac8e240790046eb72225eb2a2381f3ef5a7a88291fffc702ba08503cc2a1341")
-	TestnetGenesisHash = common.HexToHash("0x3caf9a977e579b4de001956508b57563a4b61742c66f49323a1294ad214da29d")
-	TaipeiGenesisHash  = common.HexToHash("0x13e85a0207f2888ac9c1746c94d5d7fd87ff637cbd080b42d5db1252341f4428")
-	YilanGenesisHash   = common.HexToHash("0x6b1a94b5e4c24665942a3b768bd98b39d61771a5eaba97c0466644d78d8a2f11")
+	MainnetGenesisHash = common.HexToHash("0xa48b24e2e500e3a7f222673c240dcef6c4c4fd720e6c4653349adc6acae96fb8")
+	TestnetGenesisHash = common.HexToHash("0xf67217d7715cea0b2e8acada9b6a8e538fc3df0129dab32f8c1f6baff7a50034")
+	TaipeiGenesisHash  = common.HexToHash("0xdcf32f39178f33cea762dd0e87e2be1eb9327997cb9cf20ef0645030d3ece6be")
+	YilanGenesisHash   = common.HexToHash("0xbb48abd6cc576af3d0f84173e3476045def2f57c2e891e75a8835036d7012b82")
 )
 
 // TrustedCheckpoints associates each known checkpoint with the genesis hash of