From f8d3f9f8c6741b550b738c95614a552c7056104c Mon Sep 17 00:00:00 2001
From: Jerome <wjrjerome@gmail.com>
Date: Fri, 14 Jan 2022 21:38:38 +1100
Subject: [PATCH] Xin 113 is epoch switch (#37)

* add isEpochSwitch function and refactor utils

* fix broken first v2 epoch switch block

* use adaptor epoch switch function to determine v1 v2 epoch swtich block

* add test for the GetMasternodesByNumber and GetCurrentEpochSwitchBlock function

* add v2 test for isAuthroisedAddress

* Use GetCurrentEpochSwitchBlock in findNearestSignedBlock api
---
 consensus/XDPoS/XDPoS.go                      |  55 ++++--
 consensus/XDPoS/engines/engine_v1/engine.go   |  94 +++++-----
 consensus/XDPoS/engines/engine_v1/snapshot.go |   2 +-
 consensus/XDPoS/engines/engine_v1/utils.go    | 112 ++++++++++++
 .../XDPoS/engines/engine_v1/utils_test.go     |  49 ++++++
 consensus/XDPoS/engines/engine_v2/engine.go   |  56 +++++-
 consensus/XDPoS/engines/engine_v2/utils.go    |  59 +++++++
 consensus/XDPoS/utils/utils.go                | 162 ------------------
 consensus/XDPoS/utils/utils_test.go           |  44 +----
 consensus/tests/adaptor_test.go               |  75 +++++++-
 consensus/tests/authorised_masternode_test.go |  44 ++++-
 consensus/tests/test_helper.go                |  14 +-
 contracts/utils.go                            |   3 +-
 core/block_validator_test.go                  |   3 +-
 core/blockchain.go                            |  35 +++-
 eth/api_backend.go                            |  12 +-
 eth/backend.go                                |   8 +-
 internal/ethapi/api.go                        |  54 +++---
 internal/ethapi/backend.go                    |   4 +-
 les/backend.go                                |   2 +-
 miner/worker.go                               |  51 ++++--
 21 files changed, 589 insertions(+), 349 deletions(-)
 create mode 100644 consensus/XDPoS/engines/engine_v1/utils.go
 create mode 100644 consensus/XDPoS/engines/engine_v1/utils_test.go
 create mode 100644 consensus/XDPoS/engines/engine_v2/utils.go

diff --git a/consensus/XDPoS/XDPoS.go b/consensus/XDPoS/XDPoS.go
index e41b1135f3..ecfa762834 100644
--- a/consensus/XDPoS/XDPoS.go
+++ b/consensus/XDPoS/XDPoS.go
@@ -35,8 +35,13 @@ import (
 	lru "github.com/hashicorp/golang-lru"
 )
 
-func SigHash(header *types.Header) (hash common.Hash) {
-	return utils.SigHash(header)
+func (x *XDPoS) SigHash(header *types.Header) (hash common.Hash) {
+	switch x.config.BlockConsensusVersion(header.Number) {
+	case params.ConsensusEngineVersion2:
+		return x.EngineV2.SignHash(header)
+	default: // Default "v1"
+		return x.EngineV1.SigHash(header)
+	}
 }
 
 // XDPoS is the delegated-proof-of-stake consensus engine proposed to support the
@@ -240,12 +245,12 @@ func (x *XDPoS) GetPeriod() uint64 {
 	return x.config.Period
 }
 
-func (x *XDPoS) IsAuthorisedAddress(header *types.Header, chain consensus.ChainReader, address common.Address) bool {
+func (x *XDPoS) IsAuthorisedAddress(chain consensus.ChainReader, header *types.Header, address common.Address) bool {
 	switch x.config.BlockConsensusVersion(header.Number) {
 	case params.ConsensusEngineVersion2:
-		return x.EngineV2.IsAuthorisedAddress(header, chain, address)
+		return x.EngineV2.IsAuthorisedAddress(chain, header, address)
 	default: // Default "v1"
-		return x.EngineV1.IsAuthorisedAddress(header, chain, address)
+		return x.EngineV1.IsAuthorisedAddress(chain, header, address)
 	}
 }
 
@@ -258,6 +263,20 @@ func (x *XDPoS) GetMasternodes(chain consensus.ChainReader, header *types.Header
 	}
 }
 
+func (x *XDPoS) GetMasternodesByNumber(chain consensus.ChainReader, blockNumber uint64) []common.Address {
+	blockHeader := chain.GetHeaderByNumber(blockNumber)
+	if blockHeader == nil {
+		log.Error("[GetMasternodesByNumber] Unable to find block", "Num", blockNumber)
+		return []common.Address{}
+	}
+	switch x.config.BlockConsensusVersion(big.NewInt(int64(blockNumber))) {
+	case params.ConsensusEngineVersion2:
+		return x.EngineV2.GetMasternodes(chain, blockHeader)
+	default: // Default "v1"
+		return x.EngineV1.GetMasternodes(chain, blockHeader)
+	}
+}
+
 func (x *XDPoS) YourTurn(chain consensus.ChainReader, parent *types.Header, signer common.Address) (int, int, int, bool, error) {
 	switch x.config.BlockConsensusVersion(parent.Number) {
 	case params.ConsensusEngineVersion2:
@@ -302,30 +321,34 @@ func (x *XDPoS) RecoverValidator(header *types.Header) (common.Address, error) {
 }
 
 // Get master nodes over extra data of previous checkpoint block.
-func (x *XDPoS) GetMasternodesFromCheckpointHeader(preCheckpointHeader *types.Header, n, e uint64) []common.Address {
-	switch x.config.BlockConsensusVersion(preCheckpointHeader.Number) {
+func (x *XDPoS) GetMasternodesFromCheckpointHeader(checkpointHeader *types.Header) []common.Address {
+	switch x.config.BlockConsensusVersion(checkpointHeader.Number) {
 	case params.ConsensusEngineVersion2:
-		return x.EngineV2.GetMasternodesFromEpochSwitchHeader(preCheckpointHeader)
+		return x.EngineV2.GetMasternodesFromEpochSwitchHeader(checkpointHeader)
 	default: // Default "v1"
-		return x.EngineV1.GetMasternodesFromCheckpointHeader(preCheckpointHeader, n, e)
+		return x.EngineV1.GetMasternodesFromCheckpointHeader(checkpointHeader)
 	}
 }
 
 // Check is epoch switch (checkpoint) block
-func (x *XDPoS) IsEpochSwitch(header *types.Header) bool {
+func (x *XDPoS) IsEpochSwitch(header *types.Header) (bool, uint64, error) {
 	switch x.config.BlockConsensusVersion(header.Number) {
 	case params.ConsensusEngineVersion2:
-		b, _, err := x.EngineV2.IsEpochSwitch(header)
-		if err != nil {
-			log.Error("[IsEpochSwitch] Adaptor v2 IsEpochSwitch has error", "err", err)
-			return false
-		}
-		return b
+		return x.EngineV2.IsEpochSwitch(header)
 	default: // Default "v1"
 		return x.EngineV1.IsEpochSwitch(header)
 	}
 }
 
+func (x *XDPoS) GetCurrentEpochSwitchBlock(chain consensus.ChainReader, blockNumber *big.Int) (uint64, uint64, error) {
+	switch x.config.BlockConsensusVersion(blockNumber) {
+	case params.ConsensusEngineVersion2:
+		return x.EngineV2.GetCurrentEpochSwitchBlock(chain, blockNumber)
+	default: // Default "v1"
+		return x.EngineV1.GetCurrentEpochSwitchBlock(blockNumber)
+	}
+}
+
 // Same DB across all consensus engines
 func (x *XDPoS) GetDb() ethdb.Database {
 	return x.db
diff --git a/consensus/XDPoS/engines/engine_v1/engine.go b/consensus/XDPoS/engines/engine_v1/engine.go
index c2351de31b..6aac555f86 100644
--- a/consensus/XDPoS/engines/engine_v1/engine.go
+++ b/consensus/XDPoS/engines/engine_v1/engine.go
@@ -53,6 +53,23 @@ type XDPoS_v1 struct {
 	HookGetSignersFromContract func(blockHash common.Hash) ([]common.Address, error)
 }
 
+/* V1 Block
+SignerFn is a signer callback function to request a hash to be signed by a
+backing account.
+type SignerFn func(accounts.Account, []byte) ([]byte, error)
+
+sigHash returns the hash which is used as input for the delegated-proof-of-stake
+signing. It is the hash of the entire header apart from the 65 byte signature
+contained at the end of the extra data.
+
+Note, the method requires the extra data to be at least 65 bytes, otherwise it
+panics. This is done to avoid accidentally using both forms (signature present
+or not), which could be abused to produce different hashes for the same header.
+*/
+func (x *XDPoS_v1) SigHash(header *types.Header) (hash common.Hash) {
+	return sigHash(header)
+}
+
 // New creates a XDPoS delegated-proof-of-stake consensus engine with the initial
 // signers set to the ones provided by the user.
 func New(config *params.XDPoSConfig, db ethdb.Database) *XDPoS_v1 {
@@ -81,7 +98,7 @@ func New(config *params.XDPoSConfig, db ethdb.Database) *XDPoS_v1 {
 // Author implements consensus.Engine, returning the Ethereum address recovered
 // from the signature in the header's extra-data section.
 func (x *XDPoS_v1) Author(header *types.Header) (common.Address, error) {
-	return utils.Ecrecover(header, x.signatures)
+	return ecrecover(header, x.signatures)
 }
 
 // VerifyHeader checks whether a header conforms to the consensus rules.
@@ -296,7 +313,7 @@ func (x *XDPoS_v1) checkSignersOnCheckpoint(chain consensus.ChainReader, header
 	return nil
 }
 
-func (x *XDPoS_v1) IsAuthorisedAddress(header *types.Header, chain consensus.ChainReader, address common.Address) bool {
+func (x *XDPoS_v1) IsAuthorisedAddress(chain consensus.ChainReader, header *types.Header, address common.Address) bool {
 	snap, err := x.GetSnapshot(chain, header)
 	if err != nil {
 		log.Error("[IsAuthorisedAddress] Can't get snapshot with at ", "number", header.Number, "hash", header.Hash().Hex(), "err", err)
@@ -330,36 +347,37 @@ func (x *XDPoS_v1) StoreSnapshot(snap *SnapshotV1) error {
 	return snap.store(x.db)
 }
 
-func position(list []common.Address, x common.Address) int {
-	for i, item := range list {
-		if item == x {
-			return i
-		}
-	}
-	return -1
-}
-
 func (x *XDPoS_v1) GetMasternodes(chain consensus.ChainReader, header *types.Header) []common.Address {
 	n := header.Number.Uint64()
 	e := x.config.Epoch
 	switch {
 	case n%e == 0:
-		return x.GetMasternodesFromCheckpointHeader(header, n, e)
+		return x.GetMasternodesFromCheckpointHeader(header)
 	case n%e != 0:
 		h := chain.GetHeaderByNumber(n - (n % e))
-		return x.GetMasternodesFromCheckpointHeader(h, n, e)
+		if h == nil {
+			log.Warn("[GetMasternodes v1] epoch switch block header nil", "BlockNum", n)
+		}
+		return x.GetMasternodesFromCheckpointHeader(h)
 	default:
 		return []common.Address{}
 	}
 }
 
+func (x *XDPoS_v1) GetCurrentEpochSwitchBlock(blockNumber *big.Int) (uint64, uint64, error) {
+	currentBlockNum := blockNumber.Uint64()
+	currentCheckpointNumber := currentBlockNum - currentBlockNum%x.config.Epoch
+	epochNumber := currentBlockNum / x.config.Epoch
+	return currentCheckpointNumber, epochNumber, nil
+}
+
 func (x *XDPoS_v1) GetPeriod() uint64 { return x.config.Period }
 
-func whoIsCreator(snap *SnapshotV1, header *types.Header) (common.Address, error) {
+func (x *XDPoS_v1) whoIsCreator(snap *SnapshotV1, header *types.Header) (common.Address, error) {
 	if header.Number.Uint64() == 0 {
 		return common.Address{}, errors.New("Don't take block 0")
 	}
-	m, err := utils.Ecrecover(header, snap.sigcache)
+	m, err := ecrecover(header, snap.sigcache)
 	if err != nil {
 		return common.Address{}, err
 	}
@@ -390,13 +408,13 @@ func (x *XDPoS_v1) YourTurn(chain consensus.ChainReader, parent *types.Header, s
 	// masternode[0] has chance to create block 1
 	preIndex := -1
 	if parent.Number.Uint64() != 0 {
-		pre, err = whoIsCreator(snap, parent)
+		pre, err = x.whoIsCreator(snap, parent)
 		if err != nil {
 			return 0, 0, 0, false, err
 		}
-		preIndex = position(masternodes, pre)
+		preIndex = utils.Position(masternodes, pre)
 	}
-	curIndex := position(masternodes, signer)
+	curIndex := utils.Position(masternodes, signer)
 	if signer == x.signer {
 		log.Debug("Masternodes cycle info", "number of masternodes", len(masternodes), "previous", pre, "position", preIndex, "current", signer, "position", curIndex)
 	}
@@ -524,7 +542,7 @@ func (x *XDPoS_v1) verifySeal(chain consensus.ChainReader, header *types.Header,
 	}
 
 	// Resolve the authorization key and check against signers
-	creator, err := utils.Ecrecover(header, x.signatures)
+	creator, err := ecrecover(header, x.signatures)
 	if err != nil {
 		return err
 	}
@@ -618,7 +636,7 @@ func (x *XDPoS_v1) GetValidator(creator common.Address, chain consensus.ChainRea
 			return common.Address{}, fmt.Errorf("couldn't find checkpoint header")
 		}
 	}
-	m, err := utils.GetM1M2FromCheckpointHeader(cpHeader, header, chain.Config())
+	m, err := getM1M2FromCheckpointHeader(cpHeader, header, chain.Config())
 	if err != nil {
 		return common.Address{}, err
 	}
@@ -851,7 +869,7 @@ func (x *XDPoS_v1) Seal(chain consensus.ChainReader, block *types.Block, stop <-
 	default:
 	}
 	// Sign all the things!
-	sighash, err := signFn(accounts.Account{Address: signer}, utils.SigHash(header).Bytes())
+	sighash, err := signFn(accounts.Account{Address: signer}, x.SigHash(header).Bytes())
 	if err != nil {
 		return nil, err
 	}
@@ -886,7 +904,7 @@ func (x *XDPoS_v1) calcDifficulty(chain consensus.ChainReader, parent *types.Hea
 }
 
 func (x *XDPoS_v1) RecoverSigner(header *types.Header) (common.Address, error) {
-	return utils.Ecrecover(header, x.signatures)
+	return ecrecover(header, x.signatures)
 }
 
 func (x *XDPoS_v1) RecoverValidator(header *types.Header) (common.Address, error) {
@@ -901,7 +919,7 @@ func (x *XDPoS_v1) RecoverValidator(header *types.Header) (common.Address, error
 		return common.Address{}, consensus.ErrFailValidatorSignature
 	}
 	// Recover the public key and the Ethereum address
-	pubkey, err := crypto.Ecrecover(utils.SigHash(header).Bytes(), header.Validator)
+	pubkey, err := crypto.Ecrecover(x.SigHash(header).Bytes(), header.Validator)
 	if err != nil {
 		return common.Address{}, err
 	}
@@ -912,18 +930,13 @@ func (x *XDPoS_v1) RecoverValidator(header *types.Header) (common.Address, error
 	return signer, nil
 }
 
-// Get master nodes over extra data of previous checkpoint block.
-func (x *XDPoS_v1) GetMasternodesFromCheckpointHeader(preCheckpointHeader *types.Header, n, e uint64) []common.Address {
-	if preCheckpointHeader == nil {
-		log.Info("Previous checkpoint's header is empty", "block number", n, "epoch", e)
+// Get master nodes over extra data of checkpoint block.
+func (x *XDPoS_v1) GetMasternodesFromCheckpointHeader(checkpointHeader *types.Header) []common.Address {
+	if checkpointHeader == nil {
+		log.Warn("Checkpoint's header is empty", "Header", checkpointHeader)
 		return []common.Address{}
 	}
-	masternodes := make([]common.Address, (len(preCheckpointHeader.Extra)-utils.ExtraVanity-utils.ExtraSeal)/common.AddressLength)
-	for i := 0; i < len(masternodes); i++ {
-		copy(masternodes[i][:], preCheckpointHeader.Extra[utils.ExtraVanity+i*common.AddressLength:])
-	}
-
-	return masternodes
+	return decodeMasternodesFromHeaderExtra(checkpointHeader)
 }
 
 func (x *XDPoS_v1) GetDb() ethdb.Database {
@@ -945,15 +958,6 @@ func removePenaltiesFromBlock(chain consensus.ChainReader, masternodes []common.
 	return masternodes
 }
 
-// Get masternodes address from checkpoint Header.
-func GetMasternodesFromCheckpointHeader(checkpointHeader *types.Header) []common.Address {
-	masternodes := make([]common.Address, (len(checkpointHeader.Extra)-utils.ExtraVanity-utils.ExtraSeal)/common.AddressLength)
-	for i := 0; i < len(masternodes); i++ {
-		copy(masternodes[i][:], checkpointHeader.Extra[utils.ExtraVanity+i*common.AddressLength:])
-	}
-	return masternodes
-}
-
 func (x *XDPoS_v1) getSignersFromContract(chain consensus.ChainReader, checkpointHeader *types.Header) ([]common.Address, error) {
 	startGapBlockHeader := checkpointHeader
 	number := checkpointHeader.Number.Uint64()
@@ -990,6 +994,8 @@ func NewFaker(db ethdb.Database, config *params.XDPoSConfig) *XDPoS_v1 {
 }
 
 // Epoch Switch is also known as checkpoint in v1
-func (x *XDPoS_v1) IsEpochSwitch(header *types.Header) bool {
-	return (header.Number.Uint64() % x.config.Epoch) == 0
+func (x *XDPoS_v1) IsEpochSwitch(header *types.Header) (bool, uint64, error) {
+	epochNumber := header.Number.Uint64() / x.config.Epoch
+	blockNumInEpoch := header.Number.Uint64() % x.config.Epoch
+	return blockNumInEpoch == 0, epochNumber, nil
 }
diff --git a/consensus/XDPoS/engines/engine_v1/snapshot.go b/consensus/XDPoS/engines/engine_v1/snapshot.go
index 3aa7ad030d..3ad8b22189 100644
--- a/consensus/XDPoS/engines/engine_v1/snapshot.go
+++ b/consensus/XDPoS/engines/engine_v1/snapshot.go
@@ -187,7 +187,7 @@ func (s *SnapshotV1) apply(headers []*types.Header) (*SnapshotV1, error) {
 			delete(snap.Recents, number-limit)
 		}
 		// Resolve the authorization key and check against signers
-		signer, err := utils.Ecrecover(header, s.sigcache)
+		signer, err := ecrecover(header, s.sigcache)
 		if err != nil {
 			return nil, err
 		}
diff --git a/consensus/XDPoS/engines/engine_v1/utils.go b/consensus/XDPoS/engines/engine_v1/utils.go
new file mode 100644
index 0000000000..56f1716a83
--- /dev/null
+++ b/consensus/XDPoS/engines/engine_v1/utils.go
@@ -0,0 +1,112 @@
+package engine_v1
+
+import (
+	"errors"
+
+	"github.com/XinFinOrg/XDPoSChain/common"
+	"github.com/XinFinOrg/XDPoSChain/consensus/XDPoS/utils"
+	"github.com/XinFinOrg/XDPoSChain/core/types"
+	"github.com/XinFinOrg/XDPoSChain/crypto"
+	"github.com/XinFinOrg/XDPoSChain/crypto/sha3"
+	"github.com/XinFinOrg/XDPoSChain/log"
+	"github.com/XinFinOrg/XDPoSChain/params"
+	"github.com/XinFinOrg/XDPoSChain/rlp"
+	lru "github.com/hashicorp/golang-lru"
+)
+
+// Get masternodes address from checkpoint Header.
+func decodeMasternodesFromHeaderExtra(checkpointHeader *types.Header) []common.Address {
+	masternodes := make([]common.Address, (len(checkpointHeader.Extra)-utils.ExtraVanity-utils.ExtraSeal)/common.AddressLength)
+	for i := 0; i < len(masternodes); i++ {
+		copy(masternodes[i][:], checkpointHeader.Extra[utils.ExtraVanity+i*common.AddressLength:])
+	}
+	return masternodes
+}
+
+// Get m2 list from checkpoint block.
+func getM1M2FromCheckpointHeader(checkpointHeader *types.Header, currentHeader *types.Header, config *params.ChainConfig) (map[common.Address]common.Address, error) {
+	if checkpointHeader.Number.Uint64()%common.EpocBlockRandomize != 0 {
+		return nil, errors.New("This block is not checkpoint block epoc.")
+	}
+	// Get signers from this block.
+	masternodes := decodeMasternodesFromHeaderExtra(checkpointHeader)
+	validators := utils.ExtractValidatorsFromBytes(checkpointHeader.Validators)
+	m1m2, _, err := getM1M2(masternodes, validators, currentHeader, config)
+	if err != nil {
+		return map[common.Address]common.Address{}, err
+	}
+	return m1m2, nil
+}
+
+func getM1M2(masternodes []common.Address, validators []int64, currentHeader *types.Header, config *params.ChainConfig) (map[common.Address]common.Address, uint64, error) {
+	m1m2 := map[common.Address]common.Address{}
+	maxMNs := len(masternodes)
+	moveM2 := uint64(0)
+	if len(validators) < maxMNs {
+		return nil, moveM2, errors.New("len(m2) is less than len(m1)")
+	}
+	if maxMNs > 0 {
+		isForked := config.IsTIPRandomize(currentHeader.Number)
+		if isForked {
+			moveM2 = ((currentHeader.Number.Uint64() % config.XDPoS.Epoch) / uint64(maxMNs)) % uint64(maxMNs)
+		}
+		for i, m1 := range masternodes {
+			m2Index := uint64(validators[i] % int64(maxMNs))
+			m2Index = (m2Index + moveM2) % uint64(maxMNs)
+			m1m2[m1] = masternodes[m2Index]
+		}
+	}
+	return m1m2, moveM2, nil
+}
+
+func sigHash(header *types.Header) (hash common.Hash) {
+	hasher := sha3.NewKeccak256()
+
+	err := rlp.Encode(hasher, []interface{}{
+		header.ParentHash,
+		header.UncleHash,
+		header.Coinbase,
+		header.Root,
+		header.TxHash,
+		header.ReceiptHash,
+		header.Bloom,
+		header.Difficulty,
+		header.Number,
+		header.GasLimit,
+		header.GasUsed,
+		header.Time,
+		header.Extra[:len(header.Extra)-65], // Yes, this will panic if extra is too short
+		header.MixDigest,
+		header.Nonce,
+	})
+	if err != nil {
+		log.Debug("Fail to encode", err)
+	}
+	hasher.Sum(hash[:0])
+	return hash
+}
+
+// ecrecover extracts the Ethereum account address from a signed header.
+func ecrecover(header *types.Header, sigcache *lru.ARCCache) (common.Address, error) {
+	// If the signature's already cached, return that
+	hash := header.Hash()
+	if address, known := sigcache.Get(hash); known {
+		return address.(common.Address), nil
+	}
+	// Retrieve the signature from the header extra-data
+	if len(header.Extra) < utils.ExtraSeal {
+		return common.Address{}, utils.ErrMissingSignature
+	}
+	signature := header.Extra[len(header.Extra)-utils.ExtraSeal:]
+
+	// Recover the public key and the Ethereum address
+	pubkey, err := crypto.Ecrecover(sigHash(header).Bytes(), signature)
+	if err != nil {
+		return common.Address{}, err
+	}
+	var signer common.Address
+	copy(signer[:], crypto.Keccak256(pubkey[1:])[12:])
+
+	sigcache.Add(hash, signer)
+	return signer, nil
+}
diff --git a/consensus/XDPoS/engines/engine_v1/utils_test.go b/consensus/XDPoS/engines/engine_v1/utils_test.go
new file mode 100644
index 0000000000..8a3ffe67dc
--- /dev/null
+++ b/consensus/XDPoS/engines/engine_v1/utils_test.go
@@ -0,0 +1,49 @@
+package engine_v1
+
+import (
+	"fmt"
+	"math/big"
+	"testing"
+
+	"github.com/XinFinOrg/XDPoSChain/common"
+	"github.com/XinFinOrg/XDPoSChain/core/types"
+	"github.com/XinFinOrg/XDPoSChain/params"
+)
+
+func TestGetM1M2FromCheckpointHeader(t *testing.T) {
+	masternodes := []common.Address{
+		common.StringToAddress("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+		common.StringToAddress("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
+		common.StringToAddress("cccccccccccccccccccccccccccccccccccccccc"),
+	}
+	validators := []int64{
+		2,
+		1,
+		0,
+	}
+	epoch := uint64(900)
+	config := &params.ChainConfig{
+		XDPoS: &params.XDPoSConfig{
+			Epoch: uint64(epoch),
+		},
+	}
+	testMoveM2 := []uint64{0, 0, 0, 1, 1, 1, 2, 2, 2, 0, 0, 0, 1, 1, 1, 2, 2, 2}
+	//try from block 3410001 to 3410018
+	for i := uint64(3464001); i <= 3464018; i++ {
+		currentNumber := int64(i)
+		currentHeader := &types.Header{
+			Number: big.NewInt(currentNumber),
+		}
+		m1m2, moveM2, err := getM1M2(masternodes, validators, currentHeader, config)
+		if err != nil {
+			t.Error("can't get m1m2", "err", err)
+		}
+		fmt.Printf("block: %v, moveM2: %v\n", currentHeader.Number.Int64(), moveM2)
+		for _, k := range masternodes {
+			fmt.Printf("m1: %v - m2: %v\n", k.Str(), m1m2[k].Str())
+		}
+		if moveM2 != testMoveM2[i-3464001] {
+			t.Error("wrong moveM2", "currentNumber", currentNumber, "want", testMoveM2[i-3464001], "have", moveM2)
+		}
+	}
+}
diff --git a/consensus/XDPoS/engines/engine_v2/engine.go b/consensus/XDPoS/engines/engine_v2/engine.go
index fc91eb75e6..d368c17cd2 100644
--- a/consensus/XDPoS/engines/engine_v2/engine.go
+++ b/consensus/XDPoS/engines/engine_v2/engine.go
@@ -98,6 +98,23 @@ func New(config *params.XDPoSConfig, db ethdb.Database) *XDPoS_v2 {
 	return engine
 }
 
+/* V2 Block
+SignerFn is a signer callback function to request a hash to be signed by a
+backing account.
+type SignerFn func(accounts.Account, []byte) ([]byte, error)
+
+sigHash returns the hash which is used as input for the delegated-proof-of-stake
+signing. It is the hash of the entire header apart from the 65 byte signature
+contained at the end of the extra data.
+
+Note, the method requires the extra data to be at least 65 bytes, otherwise it
+panics. This is done to avoid accidentally using both forms (signature present
+or not), which could be abused to produce different hashes for the same header.
+*/
+func (x *XDPoS_v2) SignHash(header *types.Header) (hash common.Hash) {
+	return sigHash(header)
+}
+
 // Prepare implements consensus.Engine, preparing all the consensus fields of the
 // header for running the transactions on top.
 func (x *XDPoS_v2) Prepare(chain consensus.ChainReader, header *types.Header) error {
@@ -146,7 +163,12 @@ func (x *XDPoS_v2) Prepare(chain consensus.ChainReader, header *types.Header) er
 	log.Debug("CalcDifficulty ", "number", header.Number, "difficulty", header.Difficulty)
 
 	// TODO: previous round should sit on previous Epoch and x.currentRound should >= Epoch number
-	if number%x.config.Epoch == 0 {
+	isEpochSwitchBlock, _, err := x.IsEpochSwitch(header)
+	if err != nil {
+		log.Error("[Prepare] Error while trying to determine if header is an epoch switch during Prepare", "header", header, "Error", err)
+		return err
+	}
+	if isEpochSwitchBlock {
 		snap, err := x.snapshot(chain, number-1, header.ParentHash, nil)
 		if err != nil {
 			return err
@@ -222,7 +244,7 @@ func (x *XDPoS_v2) Authorize(signer common.Address, signFn clique.SignerFn) {
 }
 
 func (x *XDPoS_v2) Author(header *types.Header) (common.Address, error) {
-	return utils.EcrecoverV2(header, x.signatures)
+	return ecrecover(header, x.signatures)
 }
 
 // Seal implements consensus.Engine, attempting to create a sealed block using
@@ -237,7 +259,11 @@ func (x *XDPoS_v2) Seal(chain consensus.ChainReader, block *types.Block, stop <-
 	}
 	// For 0-period chains, refuse to seal empty blocks (no reward but would spin sealing)
 	// checkpoint blocks have no tx
-	if x.config.Period == 0 && len(block.Transactions()) == 0 && number%x.config.Epoch != 0 {
+	isEpochSwitch, _, err := x.IsEpochSwitch(header)
+	if err != nil {
+		log.Error("[Seal] Error while checking whether header is a epoch switch during sealing", "Header", header)
+	}
+	if x.config.Period == 0 && len(block.Transactions()) == 0 && !isEpochSwitch {
 		return nil, utils.ErrWaitTransactions
 	}
 	// Don't hold the signer fields for the entire sealing procedure
@@ -271,7 +297,7 @@ func (x *XDPoS_v2) Seal(chain consensus.ChainReader, block *types.Block, stop <-
 	}
 
 	// Sign all the things!
-	signature, err := signFn(accounts.Account{Address: signer}, utils.SigHashV2(header).Bytes())
+	signature, err := signFn(accounts.Account{Address: signer}, sigHash(header).Bytes())
 	if err != nil {
 		return nil, err
 	}
@@ -327,7 +353,7 @@ func (x *XDPoS_v2) YourTurn(chain consensus.ChainReader, parent *types.Header, s
 	return len(masternodes), preIndex, curIndex, false, nil
 }
 
-func (x *XDPoS_v2) IsAuthorisedAddress(header *types.Header, chain consensus.ChainReader, address common.Address) bool {
+func (x *XDPoS_v2) IsAuthorisedAddress(chain consensus.ChainReader, header *types.Header, address common.Address) bool {
 	var extraField utils.ExtraFields_v2
 	err := utils.DecodeBytesExtraFields(header.Extra, &extraField)
 	if err != nil {
@@ -355,7 +381,7 @@ func whoIsCreator(snap *SnapshotV2, header *types.Header) (common.Address, error
 	if header.Number.Uint64() == 0 {
 		return common.Address{}, errors.New("Don't take block 0")
 	}
-	m, err := utils.EcrecoverV2(header, snap.sigcache)
+	m, err := ecrecover(header, snap.sigcache)
 	if err != nil {
 		return common.Address{}, err
 	}
@@ -1066,13 +1092,14 @@ func (x *XDPoS_v2) IsEpochSwitch(header *types.Header) (bool, uint64, error) {
 	parentRound := decodedExtraField.QuorumCert.ProposedBlockInfo.Round
 	round := decodedExtraField.Round
 	epochStart := round - round%utils.Round(x.config.Epoch)
+	epochNum := x.config.XDPoSV2Block.Uint64()/x.config.Epoch + uint64(round)/x.config.Epoch
 	// if parent is last v1 block and this is first v2 block, this is treated as epoch switch
 	if decodedExtraField.QuorumCert.ProposedBlockInfo.Number.Cmp(x.config.XDPoSV2Block) == 0 {
 		log.Info("[IsEpochSwitch] true, parent equals XDPoSV2Block", "round", round, "number", header.Number.Uint64(), "hash", header.Hash())
-		return true, x.config.XDPoSV2Block.Uint64()/x.config.Epoch + uint64(round)/x.config.Epoch, nil
+		return true, epochNum, nil
 	}
 	log.Info("[IsEpochSwitch]", "parent round", parentRound, "round", round, "number", header.Number.Uint64(), "hash", header.Hash())
-	return parentRound < epochStart, x.config.XDPoSV2Block.Uint64()/x.config.Epoch + uint64(round)/x.config.Epoch, nil
+	return parentRound < epochStart, epochNum, nil
 }
 
 // Given header and its hash, get epoch switch info from the epoch switch block of that epoch,
@@ -1133,3 +1160,16 @@ func (x *XDPoS_v2) GetMasternodes(chain consensus.ChainReader, header *types.Hea
 	}
 	return epochSwitchInfo.Masternodes
 }
+
+func (x *XDPoS_v2) GetCurrentEpochSwitchBlock(chain consensus.ChainReader, blockNum *big.Int) (uint64, uint64, error) {
+	header := chain.GetHeaderByNumber(blockNum.Uint64())
+	epochSwitchInfo, err := x.getEpochSwitchInfo(chain, header, header.Hash())
+	if err != nil {
+		log.Error("[GetCurrentEpochSwitchBlock] Fail to get epoch switch info", "Num", header.Number, "Hash", header.Hash())
+		return 0, 0, err
+	}
+
+	currentCheckpointNumber := epochSwitchInfo.EpochSwitchBlockInfo.Number.Uint64()
+	epochNum := x.config.XDPoSV2Block.Uint64()/x.config.Epoch + uint64(epochSwitchInfo.EpochSwitchBlockInfo.Round)/x.config.Epoch
+	return currentCheckpointNumber, epochNum, nil
+}
diff --git a/consensus/XDPoS/engines/engine_v2/utils.go b/consensus/XDPoS/engines/engine_v2/utils.go
new file mode 100644
index 0000000000..7414dce8cd
--- /dev/null
+++ b/consensus/XDPoS/engines/engine_v2/utils.go
@@ -0,0 +1,59 @@
+package engine_v2
+
+import (
+	"github.com/XinFinOrg/XDPoSChain/common"
+	"github.com/XinFinOrg/XDPoSChain/core/types"
+	"github.com/XinFinOrg/XDPoSChain/crypto"
+	"github.com/XinFinOrg/XDPoSChain/crypto/sha3"
+	"github.com/XinFinOrg/XDPoSChain/log"
+	"github.com/XinFinOrg/XDPoSChain/rlp"
+	lru "github.com/hashicorp/golang-lru"
+)
+
+func sigHash(header *types.Header) (hash common.Hash) {
+	hasher := sha3.NewKeccak256()
+
+	err := rlp.Encode(hasher, []interface{}{
+		header.ParentHash,
+		header.UncleHash,
+		header.Coinbase,
+		header.Root,
+		header.TxHash,
+		header.ReceiptHash,
+		header.Bloom,
+		header.Difficulty,
+		header.Number,
+		header.GasLimit,
+		header.GasUsed,
+		header.Time,
+		header.Extra,
+		header.MixDigest,
+		header.Nonce,
+		header.Validators,
+		header.Penalties,
+	})
+	if err != nil {
+		log.Debug("Fail to encode", err)
+	}
+	hasher.Sum(hash[:0])
+	return hash
+}
+
+func ecrecover(header *types.Header, sigcache *lru.ARCCache) (common.Address, error) {
+	// If the signature's already cached, return that
+	hash := header.Hash()
+	if address, known := sigcache.Get(hash); known {
+		return address.(common.Address), nil
+	}
+
+	// Recover the public key and the Ethereum address
+	pubkey, err := crypto.Ecrecover(sigHash(header).Bytes(), header.Validator)
+	if err != nil {
+		return common.Address{}, err
+	}
+	var signer common.Address
+	copy(signer[:], crypto.Keccak256(pubkey[1:])[12:])
+
+	sigcache.Add(hash, signer)
+	return signer, nil
+}
diff --git a/consensus/XDPoS/utils/utils.go b/consensus/XDPoS/utils/utils.go
index 504c72a474..4c3d5a90a1 100644
--- a/consensus/XDPoS/utils/utils.go
+++ b/consensus/XDPoS/utils/utils.go
@@ -2,20 +2,14 @@ package utils
 
 import (
 	"bytes"
-	"errors"
 	"fmt"
 	"reflect"
 	"sort"
 	"strconv"
 
 	"github.com/XinFinOrg/XDPoSChain/common"
-	"github.com/XinFinOrg/XDPoSChain/core/types"
-	"github.com/XinFinOrg/XDPoSChain/crypto"
-	"github.com/XinFinOrg/XDPoSChain/crypto/sha3"
 	"github.com/XinFinOrg/XDPoSChain/log"
-	"github.com/XinFinOrg/XDPoSChain/params"
 	"github.com/XinFinOrg/XDPoSChain/rlp"
-	lru "github.com/hashicorp/golang-lru"
 )
 
 func Position(list []common.Address, x common.Address) int {
@@ -55,51 +49,6 @@ func ExtractValidatorsFromBytes(byteValidators []byte) []int64 {
 	return validators
 }
 
-// Get masternodes address from checkpoint Header.
-func GetMasternodesFromCheckpointHeader(checkpointHeader *types.Header) []common.Address {
-	masternodes := make([]common.Address, (len(checkpointHeader.Extra)-ExtraVanity-ExtraSeal)/common.AddressLength)
-	for i := 0; i < len(masternodes); i++ {
-		copy(masternodes[i][:], checkpointHeader.Extra[ExtraVanity+i*common.AddressLength:])
-	}
-	return masternodes
-}
-
-// Get m2 list from checkpoint block.
-func GetM1M2FromCheckpointHeader(checkpointHeader *types.Header, currentHeader *types.Header, config *params.ChainConfig) (map[common.Address]common.Address, error) {
-	if checkpointHeader.Number.Uint64()%common.EpocBlockRandomize != 0 {
-		return nil, errors.New("This block is not checkpoint block epoc.")
-	}
-	// Get signers from this block.
-	masternodes := GetMasternodesFromCheckpointHeader(checkpointHeader)
-	validators := ExtractValidatorsFromBytes(checkpointHeader.Validators)
-	m1m2, _, err := GetM1M2(masternodes, validators, currentHeader, config)
-	if err != nil {
-		return map[common.Address]common.Address{}, err
-	}
-	return m1m2, nil
-}
-
-func GetM1M2(masternodes []common.Address, validators []int64, currentHeader *types.Header, config *params.ChainConfig) (map[common.Address]common.Address, uint64, error) {
-	m1m2 := map[common.Address]common.Address{}
-	maxMNs := len(masternodes)
-	moveM2 := uint64(0)
-	if len(validators) < maxMNs {
-		return nil, moveM2, errors.New("len(m2) is less than len(m1)")
-	}
-	if maxMNs > 0 {
-		isForked := config.IsTIPRandomize(currentHeader.Number)
-		if isForked {
-			moveM2 = ((currentHeader.Number.Uint64() % config.XDPoS.Epoch) / uint64(maxMNs)) % uint64(maxMNs)
-		}
-		for i, m1 := range masternodes {
-			m2Index := uint64(validators[i] % int64(maxMNs))
-			m2Index = (m2Index + moveM2) % uint64(maxMNs)
-			m1m2[m1] = masternodes[m2Index]
-		}
-	}
-	return m1m2, moveM2, nil
-}
-
 // compare 2 signers lists
 // return true if they are same elements, otherwise return false
 func CompareSignersLists(list1 []common.Address, list2 []common.Address) bool {
@@ -115,73 +64,6 @@ func CompareSignersLists(list1 []common.Address, list2 []common.Address) bool {
 	return reflect.DeepEqual(list1, list2)
 }
 
-// SignerFn is a signer callback function to request a hash to be signed by a
-// backing account.
-//type SignerFn func(accounts.Account, []byte) ([]byte, error)
-
-// sigHash returns the hash which is used as input for the delegated-proof-of-stake
-// signing. It is the hash of the entire header apart from the 65 byte signature
-// contained at the end of the extra data.
-//
-// Note, the method requires the extra data to be at least 65 bytes, otherwise it
-// panics. This is done to avoid accidentally using both forms (signature present
-// or not), which could be abused to produce different hashes for the same header.
-func SigHash(header *types.Header) (hash common.Hash) {
-	hasher := sha3.NewKeccak256()
-
-	err := rlp.Encode(hasher, []interface{}{
-		header.ParentHash,
-		header.UncleHash,
-		header.Coinbase,
-		header.Root,
-		header.TxHash,
-		header.ReceiptHash,
-		header.Bloom,
-		header.Difficulty,
-		header.Number,
-		header.GasLimit,
-		header.GasUsed,
-		header.Time,
-		header.Extra[:len(header.Extra)-65], // Yes, this will panic if extra is too short
-		header.MixDigest,
-		header.Nonce,
-	})
-	if err != nil {
-		log.Debug("Fail to encode", err)
-	}
-	hasher.Sum(hash[:0])
-	return hash
-}
-
-func SigHashV2(header *types.Header) (hash common.Hash) {
-	hasher := sha3.NewKeccak256()
-
-	err := rlp.Encode(hasher, []interface{}{
-		header.ParentHash,
-		header.UncleHash,
-		header.Coinbase,
-		header.Root,
-		header.TxHash,
-		header.ReceiptHash,
-		header.Bloom,
-		header.Difficulty,
-		header.Number,
-		header.GasLimit,
-		header.GasUsed,
-		header.Time,
-		header.Extra,
-		header.MixDigest,
-		header.Nonce,
-		header.Validators,
-		header.Penalties,
-	})
-	if err != nil {
-		log.Debug("Fail to encode", err)
-	}
-	hasher.Sum(hash[:0])
-	return hash
-}
-
 // Decode extra fields for consensus version >= 2 (XDPoS 2.0 and future versions)
 func DecodeBytesExtraFields(b []byte, val interface{}) error {
 	if len(b) == 0 {
@@ -196,47 +78,3 @@ func DecodeBytesExtraFields(b []byte, val interface{}) error {
 		return fmt.Errorf("consensus version %d is not defined", b[0])
 	}
 }
-
-// ecrecover extracts the Ethereum account address from a signed header.
-func Ecrecover(header *types.Header, sigcache *lru.ARCCache) (common.Address, error) {
-	// If the signature's already cached, return that
-	hash := header.Hash()
-	if address, known := sigcache.Get(hash); known {
-		return address.(common.Address), nil
-	}
-	// Retrieve the signature from the header extra-data
-	if len(header.Extra) < ExtraSeal {
-		return common.Address{}, ErrMissingSignature
-	}
-	signature := header.Extra[len(header.Extra)-ExtraSeal:]
-
-	// Recover the public key and the Ethereum address
-	pubkey, err := crypto.Ecrecover(SigHash(header).Bytes(), signature)
-	if err != nil {
-		return common.Address{}, err
-	}
-	var signer common.Address
-	copy(signer[:], crypto.Keccak256(pubkey[1:])[12:])
-
-	sigcache.Add(hash, signer)
-	return signer, nil
-}
-
-func EcrecoverV2(header *types.Header, sigcache *lru.ARCCache) (common.Address, error) {
-	// If the signature's already cached, return that
-	hash := header.Hash()
-	if address, known := sigcache.Get(hash); known {
-		return address.(common.Address), nil
-	}
-
-	// Recover the public key and the Ethereum address
-	pubkey, err := crypto.Ecrecover(SigHashV2(header).Bytes(), header.Validator)
-	if err != nil {
-		return common.Address{}, err
-	}
-	var signer common.Address
-	copy(signer[:], crypto.Keccak256(pubkey[1:])[12:])
-
-	sigcache.Add(hash, signer)
-	return signer, nil
-}
diff --git a/consensus/XDPoS/utils/utils_test.go b/consensus/XDPoS/utils/utils_test.go
index 6624f410af..995869ab1e 100644
--- a/consensus/XDPoS/utils/utils_test.go
+++ b/consensus/XDPoS/utils/utils_test.go
@@ -1,53 +1,11 @@
 package utils
 
 import (
-	"fmt"
-	"math/big"
 	"testing"
 
 	"github.com/XinFinOrg/XDPoSChain/common"
-	"github.com/XinFinOrg/XDPoSChain/core/types"
-	"github.com/XinFinOrg/XDPoSChain/params"
 )
 
-func TestGetM1M2FromCheckpointHeader(t *testing.T) {
-	masternodes := []common.Address{
-		common.StringToAddress("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
-		common.StringToAddress("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
-		common.StringToAddress("cccccccccccccccccccccccccccccccccccccccc"),
-	}
-	validators := []int64{
-		2,
-		1,
-		0,
-	}
-	epoch := uint64(900)
-	config := &params.ChainConfig{
-		XDPoS: &params.XDPoSConfig{
-			Epoch: uint64(epoch),
-		},
-	}
-	testMoveM2 := []uint64{0, 0, 0, 1, 1, 1, 2, 2, 2, 0, 0, 0, 1, 1, 1, 2, 2, 2}
-	//try from block 3410001 to 3410018
-	for i := uint64(3464001); i <= 3464018; i++ {
-		currentNumber := int64(i)
-		currentHeader := &types.Header{
-			Number: big.NewInt(currentNumber),
-		}
-		m1m2, moveM2, err := GetM1M2(masternodes, validators, currentHeader, config)
-		if err != nil {
-			t.Error("can't get m1m2", "err", err)
-		}
-		fmt.Printf("block: %v, moveM2: %v\n", currentHeader.Number.Int64(), moveM2)
-		for _, k := range masternodes {
-			fmt.Printf("m1: %v - m2: %v\n", k.Str(), m1m2[k].Str())
-		}
-		if moveM2 != testMoveM2[i-3464001] {
-			t.Error("wrong moveM2", "currentNumber", currentNumber, "want", testMoveM2[i-3464001], "have", moveM2)
-		}
-	}
-}
-
 func TestCompareSignersLists(t *testing.T) {
 	list1 := []common.Address{
 		common.StringToAddress("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
@@ -81,4 +39,4 @@ func TestCompareSignersLists(t *testing.T) {
 	if CompareSignersLists([]common.Address{common.StringToAddress("aaaaaaaaaaaaaaaa")}, []common.Address{common.StringToAddress("cccccccccccccccccccccccccccccccccccccccc")}) {
 		t.Error("Failed with list has only one signer")
 	}
-}
\ No newline at end of file
+}
diff --git a/consensus/tests/adaptor_test.go b/consensus/tests/adaptor_test.go
index 63891f8340..a13b0fef6d 100644
--- a/consensus/tests/adaptor_test.go
+++ b/consensus/tests/adaptor_test.go
@@ -40,7 +40,7 @@ func TestAdaptorShouldGetAuthorForDifferentConsensusVersion(t *testing.T) {
 		ParentHash: currentBlock.Hash(),
 		Coinbase:   common.HexToAddress(blockCoinBase),
 	}
-	err := generateSignature(backend, header)
+	err := generateSignature(backend, adaptor, header)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -66,11 +66,11 @@ func TestAdaptorGetMasternodesFromCheckpointHeader(t *testing.T) {
 	adaptor := blockchain.Engine().(*XDPoS.XDPoS)
 	headerV1 := currentBlock.Header()
 	headerV1.Extra = common.Hex2Bytes("d7830100018358444388676f312e31352e38856c696e757800000000000000000278c350152e15fa6ffc712a5a73d704ce73e2e103d9e17ae3ff2c6712e44e25b09ac5ee91f6c9ff065551f0dcac6f00cae11192d462db709be3758ccef312ee5eea8d7bad5374c6a652150515d744508b61c1a4deb4e4e7bf057e4e3824c11fd2569bcb77a52905cda63b5a58507910bed335e4c9d87ae0ecdfafd400")
-	masternodesV1 := adaptor.GetMasternodesFromCheckpointHeader(headerV1, 0, 0)
+	masternodesV1 := adaptor.GetMasternodesFromCheckpointHeader(headerV1)
 	headerV2 := currentBlock.Header()
 	headerV2.Number.Add(blockchain.Config().XDPoS.XDPoSV2Block, big.NewInt(1))
 	headerV2.Validators = common.Hex2Bytes("0278c350152e15fa6ffc712a5a73d704ce73e2e103d9e17ae3ff2c6712e44e25b09ac5ee91f6c9ff065551f0dcac6f00cae11192d462db709be3758c")
-	masternodesV2 := adaptor.GetMasternodesFromCheckpointHeader(headerV2, 0, 0)
+	masternodesV2 := adaptor.GetMasternodesFromCheckpointHeader(headerV2)
 	assert.True(t, reflect.DeepEqual(masternodesV1, masternodesV2), "GetMasternodesFromCheckpointHeader in adaptor for v1 v2 not equal", "v1", masternodesV1, "v2", masternodesV2)
 }
 func TestAdaptorIsEpochSwitch(t *testing.T) {
@@ -79,9 +79,15 @@ func TestAdaptorIsEpochSwitch(t *testing.T) {
 	header := currentBlock.Header()
 	// v1
 	header.Number.SetUint64(0)
-	assert.True(t, adaptor.IsEpochSwitch(header), "header should be epoch switch", header)
+
+	isEpochSwitchBlock, epochNum, err := adaptor.IsEpochSwitch(header)
+	assert.Nil(t, err)
+	assert.True(t, isEpochSwitchBlock, "header should be epoch switch", header)
+	assert.Equal(t, uint64(0), epochNum)
 	header.Number.SetUint64(1)
-	assert.False(t, adaptor.IsEpochSwitch(header), "header should not be epoch switch", header)
+	isEpochSwitchBlock, _, err = adaptor.IsEpochSwitch(header)
+	assert.Nil(t, err)
+	assert.False(t, isEpochSwitchBlock, "header should not be epoch switch", header)
 	// v2
 	parentBlockInfo := &utils.BlockInfo{
 		Hash:   header.ParentHash,
@@ -100,7 +106,9 @@ func TestAdaptorIsEpochSwitch(t *testing.T) {
 	assert.Nil(t, err)
 	header.Extra = extraBytes
 	header.Number.Add(blockchain.Config().XDPoS.XDPoSV2Block, big.NewInt(1))
-	assert.True(t, adaptor.IsEpochSwitch(header), "header should be epoch switch", header)
+	isEpochSwitchBlock, _, err = adaptor.IsEpochSwitch(header)
+	assert.Nil(t, err)
+	assert.True(t, isEpochSwitchBlock, "header should be epoch switch", header)
 	parentBlockInfo = &utils.BlockInfo{
 		Hash:   header.ParentHash,
 		Round:  utils.Round(1),
@@ -118,7 +126,9 @@ func TestAdaptorIsEpochSwitch(t *testing.T) {
 	assert.Nil(t, err)
 	header.Extra = extraBytes
 	header.Number.Add(blockchain.Config().XDPoS.XDPoSV2Block, big.NewInt(2))
-	assert.False(t, adaptor.IsEpochSwitch(header), "header should not be epoch switch", header)
+	isEpochSwitchBlock, _, err = adaptor.IsEpochSwitch(header)
+	assert.Nil(t, err)
+	assert.False(t, isEpochSwitchBlock, "header should not be epoch switch", header)
 	parentBlockInfo = &utils.BlockInfo{
 		Hash:   header.ParentHash,
 		Round:  utils.Round(blockchain.Config().XDPoS.Epoch) - 1,
@@ -136,7 +146,9 @@ func TestAdaptorIsEpochSwitch(t *testing.T) {
 	assert.Nil(t, err)
 	header.Extra = extraBytes
 	header.Number.Add(blockchain.Config().XDPoS.XDPoSV2Block, big.NewInt(101))
-	assert.True(t, adaptor.IsEpochSwitch(header), "header should be epoch switch", header)
+	isEpochSwitchBlock, _, err = adaptor.IsEpochSwitch(header)
+	assert.Nil(t, err)
+	assert.True(t, isEpochSwitchBlock, "header should be epoch switch", header)
 	parentBlockInfo = &utils.BlockInfo{
 		Hash:   header.ParentHash,
 		Round:  utils.Round(blockchain.Config().XDPoS.Epoch) + 1,
@@ -154,7 +166,9 @@ func TestAdaptorIsEpochSwitch(t *testing.T) {
 	assert.Nil(t, err)
 	header.Extra = extraBytes
 	header.Number.Add(blockchain.Config().XDPoS.XDPoSV2Block, big.NewInt(101))
-	assert.False(t, adaptor.IsEpochSwitch(header), "header should not be epoch switch", header)
+	isEpochSwitchBlock, _, err = adaptor.IsEpochSwitch(header)
+	assert.Nil(t, err)
+	assert.False(t, isEpochSwitchBlock, "header should not be epoch switch", header)
 }
 
 func TestAdaptorGetMasternodesV2(t *testing.T) {
@@ -173,6 +187,8 @@ func TestAdaptorGetMasternodesV2(t *testing.T) {
 	}
 	masternodes1 := adaptor.GetMasternodes(blockchain, currentBlock.Header())
 	assert.Equal(t, 3, len(masternodes1))
+	masternodes1ByNumber := adaptor.GetMasternodesByNumber(blockchain, currentBlock.NumberU64())
+	assert.True(t, reflect.DeepEqual(masternodes1, masternodes1ByNumber), "at block number", blockNum)
 	for blockNum = 12; blockNum < 15; blockNum++ {
 		blockHeader = createBlock(params.TestXDPoSMockChainConfigWithV2Engine, currentBlock, blockNum, int64(blockNum-10), blockCoinBase, signer, signFn)
 		currentBlock, err = insertBlock(blockchain, blockHeader)
@@ -181,5 +197,46 @@ func TestAdaptorGetMasternodesV2(t *testing.T) {
 		}
 		masternodes2 := adaptor.GetMasternodes(blockchain, currentBlock.Header())
 		assert.True(t, reflect.DeepEqual(masternodes1, masternodes2), "at block number", blockNum)
+		masternodes2ByNumber := adaptor.GetMasternodesByNumber(blockchain, currentBlock.NumberU64())
+		assert.True(t, reflect.DeepEqual(masternodes2, masternodes2ByNumber), "at block number", blockNum)
+	}
+}
+
+func TestGetCurrentEpochSwitchBlock(t *testing.T) {
+	blockchain, _, currentBlock, signer, signFn, _ := PrepareXDCTestBlockChainForV2Engine(t, 10, params.TestXDPoSMockChainConfigWithV2Engine, 0)
+	adaptor := blockchain.Engine().(*XDPoS.XDPoS)
+
+	// V1
+	currentCheckpointNumber, epochNum, err := adaptor.GetCurrentEpochSwitchBlock(blockchain, big.NewInt(9))
+	assert.Nil(t, err)
+	assert.Equal(t, uint64(0), currentCheckpointNumber)
+	assert.Equal(t, uint64(0), epochNum)
+
+	// V2
+	blockNum := 11
+	blockCoinBase := "0x111000000000000000000000000000000123"
+	blockHeader := createBlock(params.TestXDPoSMockChainConfigWithV2Engine, currentBlock, blockNum, 1, blockCoinBase, signer, signFn)
+	// it contains 3 master nodes
+	blockHeader.Validators = common.Hex2Bytes("0278c350152e15fa6ffc712a5a73d704ce73e2e103d9e17ae3ff2c6712e44e25b09ac5ee91f6c9ff065551f0dcac6f00cae11192d462db709be3758c")
+	// block 11 is the first v2 block, and is treated as epoch switch block
+	currentBlock, err = insertBlock(blockchain, blockHeader)
+	if err != nil {
+		t.Fatal(err)
+	}
+	currentCheckpointNumber, epochNum, err = adaptor.GetCurrentEpochSwitchBlock(blockchain, currentBlock.Number())
+	assert.Nil(t, err)
+	assert.Equal(t, uint64(11), currentCheckpointNumber)
+	assert.Equal(t, uint64(0), epochNum)
+
+	for blockNum = 12; blockNum < 15; blockNum++ {
+		blockHeader = createBlock(params.TestXDPoSMockChainConfigWithV2Engine, currentBlock, blockNum, int64(blockNum-10), blockCoinBase, signer, signFn)
+		currentBlock, err = insertBlock(blockchain, blockHeader)
+		if err != nil {
+			t.Fatal(err)
+		}
+		currentCheckpointNumber, epochNum, err := adaptor.GetCurrentEpochSwitchBlock(blockchain, currentBlock.Number())
+		assert.Nil(t, err)
+		assert.Equal(t, uint64(11), currentCheckpointNumber)
+		assert.Equal(t, uint64(0), epochNum)
 	}
 }
diff --git a/consensus/tests/authorised_masternode_test.go b/consensus/tests/authorised_masternode_test.go
index 1c899c6f33..d509400394 100644
--- a/consensus/tests/authorised_masternode_test.go
+++ b/consensus/tests/authorised_masternode_test.go
@@ -42,10 +42,10 @@ func TestIsAuthorisedMNForConsensusV1(t *testing.T) {
 	// Acc3 is the default account that is on the signerList
 
 	engine := blockchain.Engine().(*XDPoS.XDPoS)
-	isAuthorisedMN := engine.IsAuthorisedAddress(block449.Header(), blockchain, acc3Addr)
+	isAuthorisedMN := engine.IsAuthorisedAddress(blockchain, block449.Header(), acc3Addr)
 	assert.True(t, isAuthorisedMN)
 
-	isAuthorisedMN = engine.IsAuthorisedAddress(block449.Header(), blockchain, acc1Addr)
+	isAuthorisedMN = engine.IsAuthorisedAddress(blockchain, block449.Header(), acc1Addr)
 	assert.False(t, isAuthorisedMN)
 
 	// Now, let's mine another block to trigger the GAP block signerList update
@@ -62,9 +62,45 @@ func TestIsAuthorisedMNForConsensusV1(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	isAuthorisedMN = engine.IsAuthorisedAddress(block450.Header(), blockchain, acc3Addr)
+	isAuthorisedMN = engine.IsAuthorisedAddress(blockchain, block450.Header(), acc3Addr)
 	assert.False(t, isAuthorisedMN)
 
-	isAuthorisedMN = engine.IsAuthorisedAddress(block450.Header(), blockchain, acc1Addr)
+	isAuthorisedMN = engine.IsAuthorisedAddress(blockchain, block450.Header(), acc1Addr)
+	assert.True(t, isAuthorisedMN)
+}
+
+func TestIsAuthorisedMNForConsensusV2(t *testing.T) {
+	// we skip test for v1 since it's hard to make a real genesis block
+	blockchain, _, currentBlock, signer, signFn, _ := PrepareXDCTestBlockChainForV2Engine(t, 10, params.TestXDPoSMockChainConfigWithV2Engine, 0)
+	adaptor := blockchain.Engine().(*XDPoS.XDPoS)
+	blockNum := 11
+	blockCoinBase := "0x111000000000000000000000000000000123"
+	blockHeader := createBlock(params.TestXDPoSMockChainConfigWithV2Engine, currentBlock, blockNum, 1, blockCoinBase, signer, signFn)
+	// it contains 3 master nodes
+	// xdc0278C350152e15fa6FFC712a5A73D704Ce73E2E1
+	// xdc03d9e17Ae3fF2c6712E44e25B09Ac5ee91f6c9ff
+	// xdc065551F0dcAC6f00CAe11192D462db709bE3758c
+	blockHeader.Validators = common.Hex2Bytes("0278c350152e15fa6ffc712a5a73d704ce73e2e103d9e17ae3ff2c6712e44e25b09ac5ee91f6c9ff065551f0dcac6f00cae11192d462db709be3758c")
+	// block 11 is the first v2 block, and is treated as epoch switch block
+	currentBlock, err := insertBlock(blockchain, blockHeader)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// the first block will start from 1
+	isAuthorisedMN := adaptor.IsAuthorisedAddress(blockchain, currentBlock.Header(), common.HexToAddress("xdc03d9e17Ae3fF2c6712E44e25B09Ac5ee91f6c9ff"))
+	assert.True(t, isAuthorisedMN)
+	// The third address hence not valid
+	isAuthorisedMN = adaptor.IsAuthorisedAddress(blockchain, currentBlock.Header(), common.HexToAddress("xdc065551F0dcAC6f00CAe11192D462db709bE3758c"))
+	assert.False(t, isAuthorisedMN)
+
+	for blockNum = 12; blockNum < 16; blockNum++ {
+		blockHeader = createBlock(params.TestXDPoSMockChainConfigWithV2Engine, currentBlock, blockNum, int64(blockNum-10), blockCoinBase, signer, signFn)
+		currentBlock, err = insertBlock(blockchain, blockHeader)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+	isAuthorisedMN = adaptor.IsAuthorisedAddress(blockchain, currentBlock.Header(), common.HexToAddress("xdc065551F0dcAC6f00CAe11192D462db709bE3758c"))
 	assert.True(t, isAuthorisedMN)
 }
diff --git a/consensus/tests/test_helper.go b/consensus/tests/test_helper.go
index 746c603ef5..51fb51bae1 100644
--- a/consensus/tests/test_helper.go
+++ b/consensus/tests/test_helper.go
@@ -262,6 +262,10 @@ func PrepareXDCTestBlockChain(t *testing.T, numOfBlocks int, chainConfig *params
 	if err != nil {
 		t.Fatal(err)
 	}
+	go func() {
+		checkpointChanMsg := <-core.CheckpointCh
+		log.Info("[V1] Got a message from core CheckpointChan!", "msg", checkpointChanMsg)
+	}()
 
 	return blockchain, backend, currentBlock, signer
 }
@@ -320,6 +324,10 @@ func PrepareXDCTestBlockChainForV2Engine(t *testing.T, numOfBlocks int, chainCon
 	if err != nil {
 		t.Fatal(err)
 	}
+	go func() {
+		checkpointChanMsg := <-core.CheckpointCh
+		log.Info("[V2] Got a message from core CheckpointChan!", "msg", checkpointChanMsg)
+	}()
 
 	return blockchain, backend, currentBlock, signer, signFn, currentForkBlock
 }
@@ -385,13 +393,13 @@ func createBlock(chainConfig *params.ChainConfig, startingBlock *types.Block, bl
 	return header
 }
 
-func generateSignature(backend *backends.SimulatedBackend, header *types.Header) error {
+func generateSignature(backend *backends.SimulatedBackend, adaptor *XDPoS.XDPoS, header *types.Header) error {
 	signer, signFn, err := backends.SimulateWalletAddressAndSignFn()
 	if err != nil {
 		panic(fmt.Errorf("Error while creating simulated wallet for generating singer address and signer fn: %v", err))
 	}
 
-	signature, err := signFn(accounts.Account{Address: signer}, utils.SigHashV2(header).Bytes())
+	signature, err := signFn(accounts.Account{Address: signer}, adaptor.SigHash(header).Bytes())
 	if err != nil {
 		return err
 	}
@@ -488,7 +496,7 @@ func createXDPoSTestBlock(bc *BlockChain, customHeader *types.Header, txs []*typ
 		Time:        big.NewInt(customHeader.Number.Int64() * 10),
 		Extra:       customHeader.Extra,
 		Validator:   customHeader.Validator,
-		Validators:   customHeader.Validators,
+		Validators:  customHeader.Validators,
 	}
 	var block *types.Block
 	if len(txs) == 0 {
diff --git a/contracts/utils.go b/contracts/utils.go
index 66ec359163..d521049884 100644
--- a/contracts/utils.go
+++ b/contracts/utils.go
@@ -352,8 +352,7 @@ func GetRewardForCheckpoint(c *XDPoS.XDPoS, chain consensus.ChainReader, header
 		}
 	}
 	header = chain.GetHeader(header.ParentHash, prevCheckpoint)
-	//TODO: i think this should be c.GetMasternodesFrom...
-	masternodes := utils.GetMasternodesFromCheckpointHeader(header)
+	masternodes := c.GetMasternodesFromCheckpointHeader(header)
 
 	for i := startBlockNumber; i <= endBlockNumber; i++ {
 		if i%common.MergeSignRange == 0 || !chain.Config().IsTIP2019(big.NewInt(int64(i))) {
diff --git a/core/block_validator_test.go b/core/block_validator_test.go
index d1f7086ba0..14c43c8d0e 100644
--- a/core/block_validator_test.go
+++ b/core/block_validator_test.go
@@ -17,11 +17,12 @@
 package core
 
 import (
-	"github.com/XinFinOrg/XDPoSChain/core/rawdb"
 	"runtime"
 	"testing"
 	"time"
 
+	"github.com/XinFinOrg/XDPoSChain/core/rawdb"
+
 	"github.com/XinFinOrg/XDPoSChain/consensus/ethash"
 	"github.com/XinFinOrg/XDPoSChain/core/types"
 	"github.com/XinFinOrg/XDPoSChain/core/vm"
diff --git a/core/blockchain.go b/core/blockchain.go
index b90b0fe372..2882ce25f4 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -1590,8 +1590,13 @@ func (bc *BlockChain) insertChain(chain types.Blocks) (int, []interface{}, []*ty
 					bc.reportBlock(block, nil, err)
 					return i, events, coalescedLogs, err
 				}
-				if (block.NumberU64() % bc.chainConfig.XDPoS.Epoch) == 0 {
-					if err := tradingService.UpdateMediumPriceBeforeEpoch(block.NumberU64()/bc.chainConfig.XDPoS.Epoch, tradingState, statedb); err != nil {
+				isEpochSwithBlock, epochNumber, err := engine.IsEpochSwitch(block.Header())
+				if err != nil {
+					log.Error("[insertChain] Error while checking if the incoming block is epoch switch block", "Hash", block.Hash(), "Number", block.Number())
+					bc.reportBlock(block, nil, err)
+				}
+				if isEpochSwithBlock {
+					if err := tradingService.UpdateMediumPriceBeforeEpoch(epochNumber, tradingState, statedb); err != nil {
 						return i, events, coalescedLogs, err
 					}
 				} else {
@@ -1708,9 +1713,13 @@ func (bc *BlockChain) insertChain(chain types.Blocks) (int, []interface{}, []*ty
 		stats.report(chain, i, dirty)
 		if bc.chainConfig.XDPoS != nil {
 			// epoch block
-			if (chain[i].NumberU64() % bc.chainConfig.XDPoS.Epoch) == 0 {
+			isEpochSwithBlock, _, err := engine.IsEpochSwitch(chain[i].Header())
+			if err != nil {
+				log.Error("[insertChain] Error while checking and notifying channel CheckpointCh if the incoming block is epoch switch block", "Hash", block.Hash(), "Number", block.Number())
+				bc.reportBlock(block, nil, err)
+			}
+			if isEpochSwithBlock {
 				CheckpointCh <- 1
-
 			}
 		}
 	}
@@ -1855,8 +1864,15 @@ func (bc *BlockChain) getResultBlock(block *types.Block, verifiedM2 bool) (*Resu
 				bc.reportBlock(block, nil, err)
 				return nil, err
 			}
-			if (block.NumberU64() % bc.chainConfig.XDPoS.Epoch) == 0 {
-				if err := tradingService.UpdateMediumPriceBeforeEpoch(block.NumberU64()/bc.chainConfig.XDPoS.Epoch, tradingState, statedb); err != nil {
+
+			isEpochSwithBlock, epochNumber, err := engine.IsEpochSwitch(block.Header())
+			if err != nil {
+				log.Error("[getResultBlock] Error while checking block is epoch switch block", "Hash", block.Hash(), "Number", block.Number())
+				bc.reportBlock(block, nil, err)
+			}
+
+			if isEpochSwithBlock {
+				if err := tradingService.UpdateMediumPriceBeforeEpoch(epochNumber, tradingState, statedb); err != nil {
 					return nil, err
 				}
 			} else {
@@ -2029,7 +2045,12 @@ func (bc *BlockChain) insertBlock(block *types.Block) ([]interface{}, []*types.L
 	stats.report(types.Blocks{block}, 0, dirty)
 	if bc.chainConfig.XDPoS != nil {
 		// epoch block
-		if (block.NumberU64() % bc.chainConfig.XDPoS.Epoch) == 0 {
+		isEpochSwithBlock, _, err := bc.Engine().(*XDPoS.XDPoS).IsEpochSwitch(block.Header())
+		if err != nil {
+			log.Error("[insertBlock] Error while checking if the incoming block is epoch switch block", "Hash", block.Hash(), "Number", block.Number())
+			bc.reportBlock(block, nil, err)
+		}
+		if isEpochSwithBlock {
 			CheckpointCh <- 1
 
 		}
diff --git a/eth/api_backend.go b/eth/api_backend.go
index 9285afbac5..7255c826bc 100644
--- a/eth/api_backend.go
+++ b/eth/api_backend.go
@@ -303,7 +303,17 @@ func (b *EthApiBackend) GetVotersRewards(masternodeAddr common.Address) map[comm
 	number := block.Number().Uint64()
 	engine := b.GetEngine().(*XDPoS.XDPoS)
 	foundationWalletAddr := chain.Config().XDPoS.FoudationWalletAddr
-	lastCheckpointNumber := number - (number % b.ChainConfig().XDPoS.Epoch) - b.ChainConfig().XDPoS.Epoch // calculate for 2 epochs ago
+
+	// calculate for 2 epochs ago
+	currentCheckpointNumber, _, err := engine.GetCurrentEpochSwitchBlock(chain, block.Number())
+	if err != nil {
+		log.Error("[GetVotersRewards] Fail to get GetCurrentEpochSwitchBlock for current checkpoint block", "block", block)
+	}
+	lastCheckpointNumber, _, err := engine.GetCurrentEpochSwitchBlock(chain, big.NewInt(int64(currentCheckpointNumber-1)))
+	if err != nil {
+		log.Error("[GetVotersRewards] Fail to get GetCurrentEpochSwitchBlock for last checkpoint block", "block", block)
+	}
+
 	lastCheckpointBlock := chain.GetBlockByNumber(lastCheckpointNumber)
 	rCheckpoint := chain.Config().XDPoS.RewardCheckpoint
 
diff --git a/eth/backend.go b/eth/backend.go
index e0fbf2ffb8..a2451606cb 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -267,7 +267,7 @@ func New(ctx *node.ServiceContext, config *Config, XDCXServ *XDCx.XDCX, lendingS
 					return block, false, err
 				}
 				header := block.Header()
-				sighash, err := wallet.SignHash(accounts.Account{Address: eb}, XDPoS.SigHash(header).Bytes())
+				sighash, err := wallet.SignHash(accounts.Account{Address: eb}, c.SigHash(header).Bytes())
 				if err != nil || sighash == nil {
 					log.Error("Can't get signature hash of m2", "sighash", sighash, "err", err)
 					return block, false, err
@@ -296,7 +296,7 @@ func New(ctx *node.ServiceContext, config *Config, XDCXServ *XDCx.XDCX, lendingS
 				// not genesis block
 				header = parentHeader
 			}
-			return c.IsAuthorisedAddress(header, eth.blockchain, address)
+			return c.IsAuthorisedAddress(eth.blockchain, header, address)
 		}
 
 	}
@@ -364,7 +364,7 @@ func CreateConsensusEngine(ctx *node.ServiceContext, config *ethash.Config, chai
 // APIs returns the collection of RPC services the ethereum package offers.
 // NOTE, some of these services probably need to be moved to somewhere else.
 func (s *Ethereum) APIs() []rpc.API {
-	apis := ethapi.GetAPIs(s.ApiBackend)
+	apis := ethapi.GetAPIs(s.ApiBackend, s.BlockChain())
 
 	// Append any APIs exposed explicitly by the consensus engine
 	apis = append(apis, s.engine.APIs(s.BlockChain())...)
@@ -464,7 +464,7 @@ func (s *Ethereum) ValidateMasternode() (bool, error) {
 		//check if miner's wallet is in set of validators
 		c := s.engine.(*XDPoS.XDPoS)
 
-		authorized := c.IsAuthorisedAddress(s.blockchain.CurrentHeader(), s.blockchain, eb)
+		authorized := c.IsAuthorisedAddress(s.blockchain, s.blockchain.CurrentHeader(), eb)
 		if !authorized {
 			//This miner doesn't belong to set of validators
 			return false, nil
diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index 0f64231d3c..31a78f7e40 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -27,6 +27,7 @@ import (
 	"time"
 
 	"github.com/XinFinOrg/XDPoSChain/XDCxlending/lendingstate"
+	"github.com/XinFinOrg/XDPoSChain/consensus"
 
 	"github.com/XinFinOrg/XDPoSChain/XDCx/tradingstate"
 
@@ -497,12 +498,16 @@ func (s *PrivateAccountAPI) SignAndSendTransaction(ctx context.Context, args Sen
 // PublicBlockChainAPI provides an API to access the Ethereum blockchain.
 // It offers only methods that operate on public data that is freely available to anyone.
 type PublicBlockChainAPI struct {
-	b Backend
+	b           Backend
+	chainReader consensus.ChainReader
 }
 
 // NewPublicBlockChainAPI creates a new Ethereum blockchain API.
-func NewPublicBlockChainAPI(b Backend) *PublicBlockChainAPI {
-	return &PublicBlockChainAPI{b}
+func NewPublicBlockChainAPI(b Backend, chainReader consensus.ChainReader) *PublicBlockChainAPI {
+	return &PublicBlockChainAPI{
+		b,
+		chainReader,
+	}
 }
 
 // BlockNumber returns the block number of the chain head.
@@ -694,11 +699,7 @@ func (s *PublicBlockChainAPI) GetMasternodes(ctx context.Context, b *types.Block
 		}
 		if engine, ok := s.b.GetEngine().(*XDPoS.XDPoS); ok {
 			// Get block epoc latest.
-			lastCheckpointNumber := prevBlockNumber - (prevBlockNumber % s.b.ChainConfig().XDPoS.Epoch)
-			prevCheckpointBlock, _ := s.b.BlockByNumber(ctx, rpc.BlockNumber(lastCheckpointNumber))
-			if prevCheckpointBlock != nil {
-				masternodes = engine.GetMasternodesFromCheckpointHeader(prevCheckpointBlock.Header(), curBlockNumber, s.b.ChainConfig().XDPoS.Epoch)
-			}
+			return engine.GetMasternodesByNumber(s.chainReader, prevBlockNumber), nil
 		} else {
 			log.Error("Undefined XDPoS consensus engine")
 		}
@@ -791,7 +792,7 @@ func (s *PublicBlockChainAPI) GetCandidateStatus(ctx context.Context, coinbaseAd
 
 	// Second, Find candidates that have masternode status
 	if engine, ok := s.b.GetEngine().(*XDPoS.XDPoS); ok {
-		masternodes = engine.GetMasternodesFromCheckpointHeader(header, block.Number().Uint64(), s.b.ChainConfig().XDPoS.Epoch)
+		masternodes = engine.GetMasternodesFromCheckpointHeader(header)
 		if len(masternodes) == 0 {
 			log.Error("Failed to get masternodes", "err", err, "len(masternodes)", len(masternodes), "blockNum", header.Number.Uint64())
 			result[fieldSuccess] = false
@@ -902,7 +903,7 @@ func (s *PublicBlockChainAPI) GetCandidates(ctx context.Context, epoch rpc.Epoch
 
 	// Second, Find candidates that have masternode status
 	if engine, ok := s.b.GetEngine().(*XDPoS.XDPoS); ok {
-		masternodes = engine.GetMasternodesFromCheckpointHeader(header, block.Number().Uint64(), s.b.ChainConfig().XDPoS.Epoch)
+		masternodes = engine.GetMasternodesFromCheckpointHeader(header)
 		if len(masternodes) == 0 {
 			log.Error("Failed to get masternodes", "err", err, "len(masternodes)", len(masternodes), "blockNum", header.Number.Uint64())
 			result[fieldSuccess] = false
@@ -965,21 +966,22 @@ func (s *PublicBlockChainAPI) GetCandidates(ctx context.Context, epoch rpc.Epoch
 // GetPreviousCheckpointFromEpoch returns header of the previous checkpoint
 func (s *PublicBlockChainAPI) GetPreviousCheckpointFromEpoch(ctx context.Context, epochNum rpc.EpochNumber) (rpc.BlockNumber, rpc.EpochNumber) {
 	var checkpointNumber uint64
-	epoch := s.b.ChainConfig().XDPoS.Epoch
 
+	currentCheckpointNumber, epochNumber, err := s.b.GetEngine().(*XDPoS.XDPoS).GetCurrentEpochSwitchBlock(s.chainReader, s.b.CurrentBlock().Number())
+	if err != nil {
+		log.Error("[GetPreviousCheckpointFromEpoch] Error while trying to get current epoch switch block information", "Block", s.b.CurrentBlock(), "Error", err)
+	}
 	if epochNum == rpc.LatestEpochNumber {
-		blockNumer := s.b.CurrentBlock().Number().Uint64()
-		diff := blockNumer % epoch
-		// checkpoint number
-		checkpointNumber = blockNumer - diff
-		epochNum = rpc.EpochNumber(checkpointNumber / epoch)
-		if diff > 0 {
-			epochNum += 1
-		}
+		checkpointNumber = currentCheckpointNumber
+		epochNum = rpc.EpochNumber(epochNumber)
 	} else if epochNum < 2 {
 		checkpointNumber = 0
 	} else {
-		checkpointNumber = epoch * (uint64(epochNum) - 1)
+		blockNumberBeforeCurrentEpochSwitch := currentCheckpointNumber - 1
+		checkpointNumber, _, err = s.b.GetEngine().(*XDPoS.XDPoS).GetCurrentEpochSwitchBlock(s.chainReader, big.NewInt(int64(blockNumberBeforeCurrentEpochSwitch)))
+		if err != nil {
+			log.Error("[GetPreviousCheckpointFromEpoch] Error while trying to get last epoch switch block information", "Number", blockNumberBeforeCurrentEpochSwitch, "Error", err)
+		}
 	}
 	return rpc.BlockNumber(checkpointNumber), epochNum
 }
@@ -1301,7 +1303,11 @@ func (s *PublicBlockChainAPI) findNearestSignedBlock(ctx context.Context, b *typ
 	}
 
 	// Get block epoc latest
-	checkpointNumber := signedBlockNumber - (signedBlockNumber % s.b.ChainConfig().XDPoS.Epoch)
+	checkpointNumber, _, err := s.b.GetEngine().(*XDPoS.XDPoS).GetCurrentEpochSwitchBlock(s.chainReader, big.NewInt(int64(signedBlockNumber)))
+	if err != nil {
+		log.Error("[findNearestSignedBlock] Error while trying to get current Epoch switch block", "Number", signedBlockNumber)
+	}
+
 	checkpointBlock, _ := s.b.BlockByNumber(ctx, rpc.BlockNumber(checkpointNumber))
 
 	if checkpointBlock != nil {
@@ -1385,13 +1391,9 @@ func (s *PublicBlockChainAPI) getSigners(ctx context.Context, block *types.Block
 	var err error
 	var filterSigners []common.Address
 	var signers []common.Address
-	blockNumber := block.Number().Uint64()
 
-	// Get block epoc latest.
-	checkpointNumber := blockNumber - (blockNumber % s.b.ChainConfig().XDPoS.Epoch)
-	checkpointBlock, _ := s.b.BlockByNumber(ctx, rpc.BlockNumber(checkpointNumber))
+	masternodes := engine.GetMasternodes(s.chainReader, block.Header())
 
-	masternodes := engine.GetMasternodesFromCheckpointHeader(checkpointBlock.Header(), blockNumber, s.b.ChainConfig().XDPoS.Epoch)
 	signers, err = GetSignersFromBlocks(s.b, block.NumberU64(), block.Hash(), masternodes)
 	if err != nil {
 		log.Error("Fail to get signers from block signer SC.", "error", err)
diff --git a/internal/ethapi/backend.go b/internal/ethapi/backend.go
index 7f2d297baf..34b41b71c3 100644
--- a/internal/ethapi/backend.go
+++ b/internal/ethapi/backend.go
@@ -97,7 +97,7 @@ type Backend interface {
 	GetOrderNonce(address common.Hash) (uint64, error)
 }
 
-func GetAPIs(apiBackend Backend) []rpc.API {
+func GetAPIs(apiBackend Backend, chainReader consensus.ChainReader) []rpc.API {
 	nonceLock := new(AddrLocker)
 	return []rpc.API{
 		{
@@ -108,7 +108,7 @@ func GetAPIs(apiBackend Backend) []rpc.API {
 		}, {
 			Namespace: "eth",
 			Version:   "1.0",
-			Service:   NewPublicBlockChainAPI(apiBackend),
+			Service:   NewPublicBlockChainAPI(apiBackend, chainReader),
 			Public:    true,
 		}, {
 			Namespace: "eth",
diff --git a/les/backend.go b/les/backend.go
index 3eced66bcd..b172e8fc00 100644
--- a/les/backend.go
+++ b/les/backend.go
@@ -176,7 +176,7 @@ func (s *LightDummyAPI) Mining() bool {
 // APIs returns the collection of RPC services the ethereum package offers.
 // NOTE, some of these services probably need to be moved to somewhere else.
 func (s *LightEthereum) APIs() []rpc.API {
-	return append(ethapi.GetAPIs(s.ApiBackend), []rpc.API{
+	return append(ethapi.GetAPIs(s.ApiBackend, nil), []rpc.API{
 		{
 			Namespace: "eth",
 			Version:   "1.0",
diff --git a/miner/worker.go b/miner/worker.go
index b77b93db29..16b1bf5d77 100644
--- a/miner/worker.go
+++ b/miner/worker.go
@@ -381,7 +381,11 @@ func (self *worker) wait() {
 			}
 			if work.config.XDPoS != nil {
 				// epoch block
-				if (block.NumberU64() % work.config.XDPoS.Epoch) == 0 {
+				isEpochSwitchBlock, _, err := self.engine.(*XDPoS.XDPoS).IsEpochSwitch(block.Header())
+				if err != nil {
+					log.Error("[wait] fail to check if block is epoch switch block when worker waiting", "BlockNum", block.Number(), "Hash", block.Hash())
+				}
+				if isEpochSwitchBlock {
 					core.CheckpointCh <- 1
 				}
 			}
@@ -402,7 +406,7 @@ func (self *worker) wait() {
 					log.Error("[wait] Unable to handle new proposed block", "err", err, "number", block.Number(), "hash", block.Hash())
 				}
 
-				authorized := c.IsAuthorisedAddress(block.Header(), self.chain, self.coinbase)
+				authorized := c.IsAuthorisedAddress(self.chain, block.Header(), self.coinbase)
 				if !authorized {
 					valid := false
 					masternodes := c.GetMasternodes(self.chain, block.Header())
@@ -635,13 +639,19 @@ func (self *worker) commitNewWork() {
 		lendingFinalizedTradeTransaction                                     *types.Transaction
 	)
 	feeCapacity := state.GetTRC21FeeCapacityFromStateWithCache(parent.Root(), work.state)
-	if self.config.XDPoS != nil && header.Number.Uint64()%self.config.XDPoS.Epoch != 0 {
-		pending, err := self.eth.TxPool().Pending()
+	if self.config.XDPoS != nil {
+		isEpochSwitchBlock, _, err := self.engine.(*XDPoS.XDPoS).IsEpochSwitch(header)
 		if err != nil {
-			log.Error("Failed to fetch pending transactions", "err", err)
-			return
+			log.Error("[commitNewWork] fail to check if block is epoch switch block when fetching pending transactions", "BlockNum", header.Number, "Hash", header.Hash())
+		}
+		if !isEpochSwitchBlock {
+			pending, err := self.eth.TxPool().Pending()
+			if err != nil {
+				log.Error("Failed to fetch pending transactions", "err", err)
+				return
+			}
+			txs, specialTxs = types.NewTransactionsByPriceAndNonce(self.current.signer, pending, signers, feeCapacity)
 		}
-		txs, specialTxs = types.NewTransactionsByPriceAndNonce(self.current.signer, pending, signers, feeCapacity)
 	}
 	if atomic.LoadInt32(&self.mining) == 1 {
 		wallet, err := self.eth.AccountManager().Find(accounts.Account{Address: self.coinbase})
@@ -653,16 +663,20 @@ func (self *worker) commitNewWork() {
 			XDCX := self.eth.GetXDCX()
 			XDCXLending := self.eth.GetXDCXLending()
 			if XDCX != nil && header.Number.Uint64() > self.config.XDPoS.Epoch {
-				if header.Number.Uint64()%self.config.XDPoS.Epoch == 0 {
-					err := XDCX.UpdateMediumPriceBeforeEpoch(header.Number.Uint64()/self.config.XDPoS.Epoch, work.tradingState, work.state)
+				isEpochSwitchBlock, epochNumber, err := self.engine.(*XDPoS.XDPoS).IsEpochSwitch(header)
+				if err != nil {
+					log.Error("[commitNewWork] fail to check if block is epoch switch block when performing XDCX and XDCXLending operations", "BlockNum", header.Number, "Hash", header.Hash())
+				}
+
+				if isEpochSwitchBlock {
+					err := XDCX.UpdateMediumPriceBeforeEpoch(epochNumber, work.tradingState, work.state)
 					if err != nil {
 						log.Error("Fail when update medium price last epoch", "error", err)
 						return
 					}
-				}
-				// won't grasp tx at checkpoint
-				//https://github.com/XinFinOrg/XDPoSChain-v1/pull/416
-				if header.Number.Uint64()%self.config.XDPoS.Epoch != 0 {
+				} else {
+					// won't grasp tx at checkpoint
+					//https://github.com/XinFinOrg/XDPoSChain-v1/pull/416
 					log.Debug("Start processing order pending")
 					tradingOrderPending, _ := self.eth.OrderPool().Pending()
 					log.Debug("Start processing order pending", "len", len(tradingOrderPending))
@@ -680,6 +694,7 @@ func (self *worker) commitNewWork() {
 						}
 					}
 				}
+
 				if len(tradingTxMatches) > 0 {
 					txMatchBatch := &tradingstate.TxMatchBatch{
 						Data:      tradingTxMatches,
@@ -1062,10 +1077,16 @@ func (env *Work) commitTransactions(mux *event.TypeMux, balanceFee map[common.Ad
 		}
 		go func(logs []*types.Log, tcount int) {
 			if len(logs) > 0 {
-				mux.Post(core.PendingLogsEvent{Logs: logs})
+				err := mux.Post(core.PendingLogsEvent{Logs: logs})
+				if err != nil {
+					log.Warn("[commitTransactions] Error when sending PendingLogsEvent", "LogLength", len(logs))
+				}
 			}
 			if tcount > 0 {
-				mux.Post(core.PendingStateEvent{})
+				err := mux.Post(core.PendingStateEvent{})
+				if err != nil {
+					log.Warn("[commitTransactions] Error when sending PendingStateEvent", "tcount", tcount)
+				}
 			}
 		}(cpy, env.tcount)
 	}