diff --git a/alphabet/alphabet_contract.go b/alphabet/alphabet_contract.go
index e33cf81..e31ff2a 100644
--- a/alphabet/alphabet_contract.go
+++ b/alphabet/alphabet_contract.go
@@ -7,7 +7,6 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/interop/crypto"
 	"github.com/nspcc-dev/neo-go/pkg/interop/runtime"
 	"github.com/nspcc-dev/neo-go/pkg/interop/storage"
-	"github.com/nspcc-dev/neo-go/pkg/interop/util"
 	"github.com/nspcc-dev/neofs-contract/common"
 )
 
@@ -46,7 +45,7 @@ func init() {
 // OnPayment is a callback for NEP-17 compatible native GAS and NEO contracts.
 func OnPayment(from interop.Hash160, amount int, data interface{}) {
 	caller := runtime.GetCallingScriptHash()
-	if !bytesEqual(caller, []byte(gasHash)) && !bytesEqual(caller, []byte(neoHash)) {
+	if !common.BytesEqual(caller, []byte(gasHash)) && !common.BytesEqual(caller, []byte(neoHash)) {
 		panic("onPayment: alphabet contract accepts GAS and NEO only")
 	}
 }
@@ -65,7 +64,7 @@ func Init(addrNetmap []byte, name string, index, total int) {
 	storage.Put(ctx, indexKey, index)
 	storage.Put(ctx, totalKey, total)
 
-	setSerialized(ctx, voteKey, []common.Ballot{})
+	common.SetSerialized(ctx, voteKey, []common.Ballot{})
 
 	runtime.Log(name + " contract initialized")
 }
@@ -215,11 +214,11 @@ func vote(ctx storage.Context, epoch int, id, from []byte) int {
 
 	for i := 0; i < len(candidates); i++ {
 		cnd := candidates[i]
-		if bytesEqual(cnd.ID, id) {
+		if common.BytesEqual(cnd.ID, id) {
 			voters := cnd.Voters
 
 			for j := range voters {
-				if bytesEqual(voters[j], from) {
+				if common.BytesEqual(voters[j], from) {
 					return len(voters)
 				}
 			}
@@ -244,7 +243,7 @@ func vote(ctx storage.Context, epoch int, id, from []byte) int {
 		found = 1
 	}
 
-	setSerialized(ctx, voteKey, newCandidates)
+	common.SetSerialized(ctx, voteKey, newCandidates)
 
 	return found
 }
@@ -257,12 +256,12 @@ func removeVotes(ctx storage.Context, id []byte) {
 
 	for i := 0; i < len(candidates); i++ {
 		cnd := candidates[i]
-		if !bytesEqual(cnd.ID, id) {
+		if !common.BytesEqual(cnd.ID, id) {
 			newCandidates = append(newCandidates, cnd)
 		}
 	}
 
-	setSerialized(ctx, voteKey, newCandidates)
+	common.SetSerialized(ctx, voteKey, newCandidates)
 }
 
 func getBallots(ctx storage.Context) []common.Ballot {
@@ -274,16 +273,6 @@ func getBallots(ctx storage.Context) []common.Ballot {
 	return []common.Ballot{}
 }
 
-func setSerialized(ctx storage.Context, key interface{}, value interface{}) {
-	data := binary.Serialize(value)
-	storage.Put(ctx, key, data)
-}
-
-// neo-go#1176
-func bytesEqual(a []byte, b []byte) bool {
-	return util.Equals(string(a), string(b))
-}
-
 func voteID(epoch interface{}, args [][]byte) []byte {
 	var (
 		result     []byte
diff --git a/audit/audit_contract.go b/audit/audit_contract.go
index a8d951f..eed9c88 100644
--- a/audit/audit_contract.go
+++ b/audit/audit_contract.go
@@ -7,7 +7,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/interop/iterator"
 	"github.com/nspcc-dev/neo-go/pkg/interop/runtime"
 	"github.com/nspcc-dev/neo-go/pkg/interop/storage"
-	"github.com/nspcc-dev/neo-go/pkg/interop/util"
+	"github.com/nspcc-dev/neofs-contract/common"
 )
 
 type (
@@ -78,7 +78,7 @@ func Put(rawAuditResult []byte) bool {
 
 	for i := range innerRing {
 		ir := innerRing[i]
-		if bytesEqual(ir.key, hdr.from) {
+		if common.BytesEqual(ir.key, hdr.from) {
 			presented = true
 
 			break
@@ -183,8 +183,3 @@ func newAuditHeader(input []byte) auditHeader {
 		key,
 	}
 }
-
-// neo-go#1176
-func bytesEqual(a []byte, b []byte) bool {
-	return util.Equals(string(a), string(b))
-}
diff --git a/balance/balance_contract.go b/balance/balance_contract.go
index 9b08fd2..398f616 100644
--- a/balance/balance_contract.go
+++ b/balance/balance_contract.go
@@ -3,13 +3,11 @@ package balancecontract
 import (
 	"github.com/nspcc-dev/neo-go/pkg/interop"
 	"github.com/nspcc-dev/neo-go/pkg/interop/binary"
-	"github.com/nspcc-dev/neo-go/pkg/interop/blockchain"
 	"github.com/nspcc-dev/neo-go/pkg/interop/contract"
 	"github.com/nspcc-dev/neo-go/pkg/interop/crypto"
 	"github.com/nspcc-dev/neo-go/pkg/interop/iterator"
 	"github.com/nspcc-dev/neo-go/pkg/interop/runtime"
 	"github.com/nspcc-dev/neo-go/pkg/interop/storage"
-	"github.com/nspcc-dev/neo-go/pkg/interop/util"
 	"github.com/nspcc-dev/neofs-contract/common"
 )
 
@@ -45,9 +43,6 @@ const (
 	circulation = "MainnetGAS"
 	version     = 1
 
-	voteKey   = "ballots"
-	blockDiff = 20 // change base on performance evaluation
-
 	netmapContractKey    = "netmapScriptHash"
 	containerContractKey = "containerScriptHash"
 )
@@ -134,11 +129,11 @@ func TransferX(from, to interop.Hash160, amount int, details []byte) bool {
 		runtime.Log("transferX: processed indirect invoke")
 	} else {
 		hashTxID = invokeID([]interface{}{from, to, amount}, []byte("transfer"))
-		n = vote(ctx, hashTxID, irKey)
+		n = common.Vote(ctx, hashTxID, irKey)
 	}
 
 	if n >= threshold {
-		removeVotes(ctx, hashTxID)
+		common.RemoveVotes(ctx, hashTxID)
 
 		result := token.transfer(ctx, from, to, amount, true, details)
 		if result {
@@ -166,16 +161,16 @@ func Lock(txID []byte, from, to interop.Hash160, amount, until int) bool {
 
 	hashTxID := invokeID([]interface{}{txID, from, to, amount, until}, []byte("lock"))
 
-	n := vote(ctx, hashTxID, irKey)
+	n := common.Vote(ctx, hashTxID, irKey)
 	if n >= threshold {
-		removeVotes(ctx, hashTxID)
+		common.RemoveVotes(ctx, hashTxID)
 
 		lockAccount := Account{
 			Balance: 0,
 			Until:   until,
 			Parent:  from,
 		}
-		setSerialized(ctx, to, lockAccount)
+		common.SetSerialized(ctx, to, lockAccount)
 
 		result := token.transfer(ctx, from, to, amount, true, lockTransferMsg)
 		if !result {
@@ -204,9 +199,9 @@ func NewEpoch(epochNum int) bool {
 
 	epochID := invokeID([]interface{}{epochNum}, []byte("epoch"))
 
-	n := vote(ctx, epochID, irKey)
+	n := common.Vote(ctx, epochID, irKey)
 	if n >= threshold {
-		removeVotes(ctx, epochID)
+		common.RemoveVotes(ctx, epochID)
 		it := storage.Find(ctx, []byte{})
 		for iterator.Next(it) {
 			addr := iterator.Key(it).([]byte)
@@ -243,9 +238,9 @@ func Mint(to interop.Hash160, amount int, details []byte) bool {
 
 	mintID := invokeID([]interface{}{to, amount, details}, []byte("mint"))
 
-	n := vote(ctx, mintID, irKey)
+	n := common.Vote(ctx, mintID, irKey)
 	if n >= threshold {
-		removeVotes(ctx, mintID)
+		common.RemoveVotes(ctx, mintID)
 
 		ok := token.transfer(ctx, nil, to, amount, true, details)
 		if !ok {
@@ -274,9 +269,9 @@ func Burn(from interop.Hash160, amount int, details []byte) bool {
 
 	burnID := invokeID([]interface{}{from, amount, details}, []byte("burn"))
 
-	n := vote(ctx, burnID, irKey)
+	n := common.Vote(ctx, burnID, irKey)
 	if n >= threshold {
-		removeVotes(ctx, burnID)
+		common.RemoveVotes(ctx, burnID)
 
 		ok := token.transfer(ctx, from, nil, amount, true, details)
 		if !ok {
@@ -329,14 +324,14 @@ func (t Token) transfer(ctx storage.Context, from, to interop.Hash160, amount in
 			storage.Delete(ctx, from)
 		} else {
 			amountFrom.Balance = amountFrom.Balance - amount // neo-go#953
-			setSerialized(ctx, from, amountFrom)
+			common.SetSerialized(ctx, from, amountFrom)
 		}
 	}
 
 	if len(to) == 20 {
 		amountTo := getAccount(ctx, to)
 		amountTo.Balance = amountTo.Balance + amount // neo-go#953
-		setSerialized(ctx, to, amountTo)
+		common.SetSerialized(ctx, to, amountTo)
 	}
 
 	runtime.Notify("Transfer", from, to, amount)
@@ -379,7 +374,7 @@ func isUsableAddress(addr interop.Hash160) bool {
 
 		// Check if a smart contract is calling script hash
 		callingScriptHash := runtime.GetCallingScriptHash()
-		if bytesEqual(callingScriptHash, addr) {
+		if common.BytesEqual(callingScriptHash, addr) {
 			return true
 		}
 	}
@@ -398,82 +393,6 @@ func innerRingInvoker(ir []irNode) []byte {
 	return nil
 }
 
-func vote(ctx storage.Context, id, from []byte) int {
-	var (
-		newCandidates []common.Ballot
-		candidates    = getBallots(ctx)
-		found         = -1
-		blockHeight   = blockchain.GetHeight()
-	)
-
-	for i := 0; i < len(candidates); i++ {
-		cnd := candidates[i]
-
-		if blockHeight-cnd.Height > blockDiff {
-			continue
-		}
-
-		if bytesEqual(cnd.ID, id) {
-			voters := cnd.Voters
-
-			for j := range voters {
-				if bytesEqual(voters[j], from) {
-					return len(voters)
-				}
-			}
-
-			voters = append(voters, from)
-			cnd = common.Ballot{ID: id, Voters: voters, Height: blockHeight}
-			found = len(voters)
-		}
-
-		newCandidates = append(newCandidates, cnd)
-	}
-
-	if found < 0 {
-		voters := [][]byte{from}
-		newCandidates = append(newCandidates, common.Ballot{
-			ID:     id,
-			Voters: voters,
-			Height: blockHeight})
-		found = 1
-	}
-
-	setSerialized(ctx, voteKey, newCandidates)
-
-	return found
-}
-
-func removeVotes(ctx storage.Context, id []byte) {
-	var (
-		newCandidates []common.Ballot
-		candidates    = getBallots(ctx)
-	)
-
-	for i := 0; i < len(candidates); i++ {
-		cnd := candidates[i]
-		if !bytesEqual(cnd.ID, id) {
-			newCandidates = append(newCandidates, cnd)
-		}
-	}
-
-	setSerialized(ctx, voteKey, newCandidates)
-}
-
-func getBallots(ctx storage.Context) []common.Ballot {
-	data := storage.Get(ctx, voteKey)
-	if data != nil {
-		return binary.Deserialize(data.([]byte)).([]common.Ballot)
-	}
-
-	return []common.Ballot{}
-}
-
-func setSerialized(ctx storage.Context, key interface{}, value interface{}) {
-	data := binary.Serialize(value)
-	storage.Put(ctx, key, data)
-}
-
 func getAccount(ctx storage.Context, key interface{}) Account {
 	data := storage.Get(ctx, key)
 	if data != nil {
@@ -492,11 +411,6 @@ func invokeID(args []interface{}, prefix []byte) []byte {
 	return crypto.SHA256(prefix)
 }
 
-// neo-go#1176
-func bytesEqual(a []byte, b []byte) bool {
-	return util.Equals(string(a), string(b))
-}
-
 /*
    Check if invocation made from known container or audit contracts.
    This is necessary because calls from these contracts require to do transfer
@@ -520,5 +434,5 @@ func bytesEqual(a []byte, b []byte) bool {
 func fromKnownContract(caller interop.Hash160) bool {
 	containerContractAddr := storage.Get(ctx, containerContractKey).([]byte)
 
-	return bytesEqual(caller, containerContractAddr)
+	return common.BytesEqual(caller, containerContractAddr)
 }
diff --git a/common/vote.go b/common/vote.go
new file mode 100644
index 0000000..722ff1e
--- /dev/null
+++ b/common/vote.go
@@ -0,0 +1,104 @@
+package common
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/interop/binary"
+	"github.com/nspcc-dev/neo-go/pkg/interop/blockchain"
+	"github.com/nspcc-dev/neo-go/pkg/interop/storage"
+	"github.com/nspcc-dev/neo-go/pkg/interop/util"
+)
+
+const voteKey = "ballots"
+
+const blockDiff = 20 // change base on performance evaluation
+
+func InitVote(ctx storage.Context) {
+	SetSerialized(ctx, voteKey, []Ballot{})
+}
+
+// Vote adds ballot for the decision with specific 'id' and returns amount
+// on unique voters for that decision.
+func Vote(ctx storage.Context, id, from []byte) int {
+	var (
+		newCandidates []Ballot
+		candidates    = getBallots(ctx)
+		found         = -1
+		blockHeight   = blockchain.GetHeight()
+	)
+
+	for i := 0; i < len(candidates); i++ {
+		cnd := candidates[i]
+
+		if blockHeight-cnd.Height > blockDiff {
+			continue
+		}
+
+		if BytesEqual(cnd.ID, id) {
+			voters := cnd.Voters
+
+			for j := range voters {
+				if BytesEqual(voters[j], from) {
+					return len(voters)
+				}
+			}
+
+			voters = append(voters, from)
+			cnd = Ballot{ID: id, Voters: voters, Height: blockHeight}
+			found = len(voters)
+		}
+
+		newCandidates = append(newCandidates, cnd)
+	}
+
+	if found < 0 {
+		voters := [][]byte{from}
+		newCandidates = append(newCandidates, Ballot{
+			ID:     id,
+			Voters: voters,
+			Height: blockHeight})
+		found = 1
+	}
+
+	SetSerialized(ctx, voteKey, newCandidates)
+
+	return found
+}
+
+// RemoveVotes clears ballots of the decision that has been accepted by
+// inner ring nodes.
+func RemoveVotes(ctx storage.Context, id []byte) {
+	var (
+		newCandidates []Ballot
+		candidates    = getBallots(ctx)
+	)
+
+	for i := 0; i < len(candidates); i++ {
+		cnd := candidates[i]
+		if !BytesEqual(cnd.ID, id) {
+			newCandidates = append(newCandidates, cnd)
+		}
+	}
+
+	SetSerialized(ctx, voteKey, newCandidates)
+}
+
+// getBallots returns deserialized slice of vote ballots.
+func getBallots(ctx storage.Context) []Ballot {
+	data := storage.Get(ctx, voteKey)
+	if data != nil {
+		return binary.Deserialize(data.([]byte)).([]Ballot)
+	}
+
+	return []Ballot{}
+}
+
+// BytesEqual compares two slice of bytes by wrapping them into strings,
+// which is necessary with new util.Equal interop behaviour, see neo-go#1176.
+func BytesEqual(a []byte, b []byte) bool {
+	return util.Equals(string(a), string(b))
+}
+
+// SetSerialized serializes data and puts it into contract storage.
+func SetSerialized(ctx storage.Context, key interface{}, value interface{}) {
+	data := binary.Serialize(value)
+	storage.Put(ctx, key, data)
+}
diff --git a/container/container_contract.go b/container/container_contract.go
index ac64894..89084c2 100644
--- a/container/container_contract.go
+++ b/container/container_contract.go
@@ -3,13 +3,11 @@ package containercontract
 import (
 	"github.com/nspcc-dev/neo-go/pkg/interop"
 	"github.com/nspcc-dev/neo-go/pkg/interop/binary"
-	"github.com/nspcc-dev/neo-go/pkg/interop/blockchain"
 	"github.com/nspcc-dev/neo-go/pkg/interop/contract"
 	"github.com/nspcc-dev/neo-go/pkg/interop/crypto"
 	"github.com/nspcc-dev/neo-go/pkg/interop/iterator"
 	"github.com/nspcc-dev/neo-go/pkg/interop/runtime"
 	"github.com/nspcc-dev/neo-go/pkg/interop/storage"
-	"github.com/nspcc-dev/neo-go/pkg/interop/util"
 	"github.com/nspcc-dev/neofs-contract/common"
 )
 
@@ -41,9 +39,7 @@ type (
 
 const (
 	version   = 1
-	voteKey   = "ballots"
 	ownersKey = "ownersList"
-	blockDiff = 20 // change base on performance evaluation
 
 	neofsIDContractKey = "identityScriptHash"
 	balanceContractKey = "balanceScriptHash"
@@ -123,9 +119,9 @@ func Put(container, signature, publicKey []byte) bool {
 	containerFee := contract.Call(netmapContractAddr, "config", containerFeeKey).(int)
 	hashCandidate := invokeID([]interface{}{container, signature, publicKey}, []byte("put"))
 
-	n := vote(ctx, hashCandidate, irKey)
+	n := common.Vote(ctx, hashCandidate, irKey)
 	if n >= threshold {
-		removeVotes(ctx, hashCandidate)
+		common.RemoveVotes(ctx, hashCandidate)
 		// todo: check if new container with unique container id
 
 		for i := 0; i < len(innerRing); i++ {
@@ -184,9 +180,9 @@ func Delete(containerID, signature []byte) bool {
 
 	hashCandidate := invokeID([]interface{}{containerID, signature}, []byte("delete"))
 
-	n := vote(ctx, hashCandidate, irKey)
+	n := common.Vote(ctx, hashCandidate, irKey)
 	if n >= threshold {
-		removeVotes(ctx, hashCandidate)
+		common.RemoveVotes(ctx, hashCandidate)
 		removeContainer(ctx, containerID, ownerID)
 		runtime.Log("delete: remove container")
 	} else {
@@ -214,7 +210,7 @@ func List(owner []byte) [][]byte {
 	owners := getList(ctx, ownersKey)
 	for i := 0; i < len(owners); i++ {
 		ownerID := owners[i]
-		if len(owner) != 0 && !bytesEqual(owner, ownerID) {
+		if len(owner) != 0 && !common.BytesEqual(owner, ownerID) {
 			continue
 		}
 
@@ -253,7 +249,7 @@ func SetEACL(eACL, signature []byte) bool {
 	}
 
 	key := append(eACLPrefix, containerID...)
-	setSerialized(ctx, key, rule)
+	common.SetSerialized(ctx, key, rule)
 
 	runtime.Log("setEACL: success")
 
@@ -304,7 +300,7 @@ func PutContainerSize(epoch int, cid []byte, usedSize int, pubKey interop.Public
 	// do not add estimation twice
 	for i := range s.estimations {
 		est := s.estimations[i]
-		if bytesEqual(est.from, pubKey) {
+		if common.BytesEqual(est.from, pubKey) {
 			return false
 		}
 	}
@@ -356,9 +352,9 @@ func ProcessEpoch(epochNum int) {
 	candidates := keysToDelete(epochNum)
 	epochID := invokeID([]interface{}{epochNum}, []byte("epoch"))
 
-	n := vote(ctx, epochID, irKey)
+	n := common.Vote(ctx, epochID, irKey)
 	if n >= threshold {
-		removeVotes(ctx, epochID)
+		common.RemoveVotes(ctx, epochID)
 
 		for i := range candidates {
 			candidate := candidates[i]
@@ -379,9 +375,9 @@ func StartContainerEstimation(epoch int) bool {
 
 	hashCandidate := invokeID([]interface{}{epoch}, []byte("startEstimation"))
 
-	n := vote(ctx, hashCandidate, irKey)
+	n := common.Vote(ctx, hashCandidate, irKey)
 	if n >= threshold {
-		removeVotes(ctx, hashCandidate)
+		common.RemoveVotes(ctx, hashCandidate)
 		runtime.Notify("StartEstimation", epoch)
 		runtime.Log("startEstimation: notification has been produced")
 	} else {
@@ -403,9 +399,9 @@ func StopContainerEstimation(epoch int) bool {
 
 	hashCandidate := invokeID([]interface{}{epoch}, []byte("stopEstimation"))
 
-	n := vote(ctx, hashCandidate, irKey)
+	n := common.Vote(ctx, hashCandidate, irKey)
 	if n >= threshold {
-		removeVotes(ctx, hashCandidate)
+		common.RemoveVotes(ctx, hashCandidate)
 		runtime.Notify("StopEstimation", epoch)
 		runtime.Log("stopEstimation: notification has been produced")
 	} else {
@@ -439,7 +435,7 @@ func removeContainer(ctx storage.Context, id []byte, owner []byte) {
 func addOrAppend(ctx storage.Context, key interface{}, value []byte) {
 	list := getList(ctx, key)
 	for i := 0; i < len(list); i++ {
-		if bytesEqual(list[i], value) {
+		if common.BytesEqual(list[i], value) {
 			return
 		}
 	}
@@ -450,7 +446,7 @@ func addOrAppend(ctx storage.Context, key interface{}, value []byte) {
 		list = append(list, value)
 	}
 
-	setSerialized(ctx, key, list)
+	common.SetSerialized(ctx, key, list)
 }
 
 // remove returns amount of left elements in the list
@@ -461,7 +457,7 @@ func remove(ctx storage.Context, key interface{}, value []byte) int {
 	)
 
 	for i := 0; i < len(list); i++ {
-		if !bytesEqual(list[i], value) {
+		if !common.BytesEqual(list[i], value) {
 			newList = append(newList, list[i])
 		}
 	}
@@ -470,7 +466,7 @@ func remove(ctx storage.Context, key interface{}, value []byte) int {
 	if ln == 0 {
 		storage.Delete(ctx, key)
 	} else {
-		setSerialized(ctx, key, newList)
+		common.SetSerialized(ctx, key, newList)
 	}
 
 	return ln
@@ -487,68 +483,6 @@ func innerRingInvoker(ir []irNode) []byte {
 	return nil
 }
 
-func vote(ctx storage.Context, id, from []byte) int {
-	var (
-		newCandidates []common.Ballot
-		candidates    = getBallots(ctx)
-		found         = -1
-		blockHeight   = blockchain.GetHeight()
-	)
-
-	for i := 0; i < len(candidates); i++ {
-		cnd := candidates[i]
-
-		if blockHeight-cnd.Height > blockDiff {
-			continue
-		}
-
-		if bytesEqual(cnd.ID, id) {
-			voters := cnd.Voters
-
-			for j := range voters {
-				if bytesEqual(voters[j], from) {
-					return len(voters)
-				}
-			}
-
-			voters = append(voters, from)
-			cnd = common.Ballot{ID: id, Voters: voters, Height: blockHeight}
-			found = len(voters)
-		}
-
-		newCandidates = append(newCandidates, cnd)
-	}
-
-	if found < 0 {
-		voters := [][]byte{from}
-		newCandidates = append(newCandidates, common.Ballot{
-			ID:     id,
-			Voters: voters,
-			Height: blockHeight})
-		found = 1
-	}
-
-	setSerialized(ctx, voteKey, newCandidates)
-
-	return found
-}
-
-func removeVotes(ctx storage.Context, id []byte) {
-	var (
-		newCandidates []common.Ballot
-		candidates    = getBallots(ctx)
-	)
-
-	for i := 0; i < len(candidates); i++ {
-		cnd := candidates[i]
-		if !bytesEqual(cnd.ID, id) {
-			newCandidates = append(newCandidates, cnd)
-		}
-	}
-
-	setSerialized(ctx, voteKey, newCandidates)
-}
-
 func getList(ctx storage.Context, key interface{}) [][]byte {
 	data := storage.Get(ctx, key)
 	if data != nil {
@@ -572,15 +506,6 @@ func getAllContainers(ctx storage.Context) [][]byte {
 	return list
 }
 
-func getBallots(ctx storage.Context) []common.Ballot {
-	data := storage.Get(ctx, voteKey)
-	if data != nil {
-		return binary.Deserialize(data.([]byte)).([]common.Ballot)
-	}
-
-	return []common.Ballot{}
-}
-
 func getEACL(ctx storage.Context, cid []byte) extendedACL {
 	key := append(eACLPrefix, cid...)
 	data := storage.Get(ctx, key)
@@ -591,11 +516,6 @@ func getEACL(ctx storage.Context, cid []byte) extendedACL {
 	return extendedACL{val: []byte{}, sig: []byte{}, pub: []byte{}}
 }
 
-func setSerialized(ctx storage.Context, key, value interface{}) {
-	data := binary.Serialize(value)
-	storage.Put(ctx, key, data)
-}
-
 func walletToScripHash(wallet []byte) []byte {
 	return wallet[1 : len(wallet)-4]
 }
@@ -628,7 +548,7 @@ func getOwnerByID(ctx storage.Context, id []byte) []byte {
 
 		for j := 0; j < len(containers); j++ {
 			container := containers[j]
-			if bytesEqual(container, id) {
+			if common.BytesEqual(container, id) {
 				return ownerID
 			}
 		}
@@ -637,11 +557,6 @@ func getOwnerByID(ctx storage.Context, id []byte) []byte {
 	return nil
 }
 
-// neo-go#1176
-func bytesEqual(a []byte, b []byte) bool {
-	return util.Equals(string(a), string(b))
-}
-
 func isSignedByOwnerKey(msg, sig, owner, key []byte) bool {
 	if !isOwnerFromKey(owner, key) {
 		return false
@@ -654,7 +569,7 @@ func isOwnerFromKey(owner []byte, key []byte) bool {
 	ownerSH := walletToScripHash(owner)
 	keySH := contract.CreateStandardAccount(key)
 
-	return bytesEqual(ownerSH, keySH)
+	return common.BytesEqual(ownerSH, keySH)
 }
 
 func estimationKey(epoch int, cid []byte) []byte {
@@ -688,7 +603,7 @@ func isStorageNode(key interop.PublicKey) bool {
 		nodeInfo := snapshot[i].info
 		nodeKey := nodeInfo[2:35] // offset:2, len:33
 
-		if bytesEqual(key, nodeKey) {
+		if common.BytesEqual(key, nodeKey) {
 			return true
 		}
 	}
diff --git a/neofs/neofs_contract.go b/neofs/neofs_contract.go
index cc25a6d..e2178a7 100644
--- a/neofs/neofs_contract.go
+++ b/neofs/neofs_contract.go
@@ -34,13 +34,11 @@ package smart_contract
 import (
 	"github.com/nspcc-dev/neo-go/pkg/interop"
 	"github.com/nspcc-dev/neo-go/pkg/interop/binary"
-	"github.com/nspcc-dev/neo-go/pkg/interop/blockchain"
 	"github.com/nspcc-dev/neo-go/pkg/interop/contract"
 	"github.com/nspcc-dev/neo-go/pkg/interop/crypto"
 	"github.com/nspcc-dev/neo-go/pkg/interop/iterator"
 	"github.com/nspcc-dev/neo-go/pkg/interop/runtime"
 	"github.com/nspcc-dev/neo-go/pkg/interop/storage"
-	"github.com/nspcc-dev/neo-go/pkg/interop/util"
 	"github.com/nspcc-dev/neofs-contract/common"
 )
 
@@ -69,11 +67,9 @@ const (
 	version = 3
 
 	innerRingKey     = "innerring"
-	voteKey          = "ballots"
 	candidatesKey    = "candidates"
 	cashedChequesKey = "cheques"
 
-	blockDiff        = 20 // change base on performance evaluation
 	publicKeySize    = 33
 	minInnerRingSize = 3
 
@@ -121,10 +117,10 @@ func Init(args [][]byte) bool {
 	}
 
 	// initialize all storage slices
-	setSerialized(ctx, innerRingKey, irList)
-	setSerialized(ctx, voteKey, []common.Ballot{})
-	setSerialized(ctx, candidatesKey, []node{})
-	setSerialized(ctx, cashedChequesKey, []cheque{})
+	common.SetSerialized(ctx, innerRingKey, irList)
+	common.InitVote(ctx)
+	common.SetSerialized(ctx, candidatesKey, []node{})
+	common.SetSerialized(ctx, cashedChequesKey, []cheque{})
 
 	runtime.Log("neofs: contract initialized")
 
@@ -152,14 +148,14 @@ func InnerRingCandidateRemove(key []byte) bool {
 
 	for i := range candidates {
 		c := candidates[i]
-		if !bytesEqual(c.pub, key) {
+		if !common.BytesEqual(c.pub, key) {
 			nodes = append(nodes, c)
 		} else {
 			runtime.Log("irCandidateRemove: candidate has been removed")
 		}
 	}
 
-	setSerialized(ctx, candidatesKey, nodes)
+	common.SetSerialized(ctx, candidatesKey, nodes)
 
 	return true
 }
@@ -190,7 +186,7 @@ func InnerRingCandidateAdd(key []byte) bool {
 	}
 
 	runtime.Log("irCandidateAdd: candidate has been added")
-	setSerialized(ctx, candidatesKey, list)
+	common.SetSerialized(ctx, candidatesKey, list)
 
 	return true
 }
@@ -198,12 +194,12 @@ func InnerRingCandidateAdd(key []byte) bool {
 // OnPayment is a callback for NEP-17 compatible native GAS contract.
 func OnPayment(from interop.Hash160, amount int, data interface{}) {
 	rcv := data.(interop.Hash160)
-	if bytesEqual(rcv, []byte(ignoreDepositNotification)) {
+	if common.BytesEqual(rcv, []byte(ignoreDepositNotification)) {
 		return
 	}
 
 	caller := runtime.GetCallingScriptHash()
-	if !bytesEqual(caller, []byte(tokenHash)) {
+	if !common.BytesEqual(caller, []byte(tokenHash)) {
 		panic("onPayment: only GAS can be accepted for deposit")
 	}
 
@@ -290,9 +286,9 @@ func Cheque(id, user []byte, amount int, lockAcc []byte) bool {
 		panic("cheque: non unique id")
 	}
 
-	n := vote(ctx, hashID, irKey)
+	n := common.Vote(ctx, hashID, irKey)
 	if n >= threshold {
-		removeVotes(ctx, hashID)
+		common.RemoveVotes(ctx, hashID)
 
 		from := runtime.GetExecutingScriptHash()
 
@@ -304,7 +300,7 @@ func Cheque(id, user []byte, amount int, lockAcc []byte) bool {
 
 		runtime.Log("cheque: funds have been transferred")
 
-		setSerialized(ctx, cashedChequesKey, list)
+		common.SetSerialized(ctx, cashedChequesKey, list)
 		runtime.Notify("Cheque", id, user, amount, lockAcc)
 	}
 
@@ -385,7 +381,7 @@ loop:
 		// find key in actual inner ring list
 		for j := 0; j < len(irList); j++ {
 			n := irList[j]
-			if bytesEqual(n.pub, key) {
+			if common.BytesEqual(n.pub, key) {
 				newIR = append(newIR, n)
 				oldNodes++
 
@@ -406,13 +402,13 @@ loop:
 
 	hashID := crypto.SHA256(chequeID)
 
-	n := vote(ctx, hashID, irKey)
+	n := common.Vote(ctx, hashID, irKey)
 	if n >= threshold {
-		removeVotes(ctx, hashID)
+		common.RemoveVotes(ctx, hashID)
 
-		setSerialized(ctx, candidatesKey, candidates)
-		setSerialized(ctx, innerRingKey, newIR)
-		setSerialized(ctx, cashedChequesKey, chequesList)
+		common.SetSerialized(ctx, candidatesKey, candidates)
+		common.SetSerialized(ctx, innerRingKey, newIR)
+		common.SetSerialized(ctx, cashedChequesKey, chequesList)
 
 		runtime.Notify("InnerRingUpdate", c.id, newIR)
 		runtime.Log("irUpdate: inner ring list has been updated")
@@ -431,7 +427,7 @@ func IsInnerRing(key []byte) bool {
 	for i := range irList {
 		node := irList[i]
 
-		if bytesEqual(node.pub, key) {
+		if common.BytesEqual(node.pub, key) {
 			return true
 		}
 	}
@@ -467,12 +463,12 @@ func SetConfig(id, key, val []byte) bool {
 	// vote for new configuration value
 	hashID := crypto.SHA256(id)
 
-	n := vote(ctx, hashID, irKey)
+	n := common.Vote(ctx, hashID, irKey)
 	if n >= threshold {
-		removeVotes(ctx, hashID)
+		common.RemoveVotes(ctx, hashID)
 
 		setConfig(ctx, key, val)
-		setSerialized(ctx, cashedChequesKey, chequesList)
+		common.SetSerialized(ctx, cashedChequesKey, chequesList)
 
 		runtime.Notify("SetConfig", id, key, val)
 		runtime.Log("setConfig: configuration has been updated")
@@ -539,79 +535,6 @@ func innerRingInvoker(ir []node) []byte {
 	return nil
 }
 
-// vote adds ballot for the decision with specific 'id' and returns amount
-// on unique voters for that decision.
-func vote(ctx storage.Context, id, from []byte) int {
-	var (
-		newCandidates = []common.Ballot{} // it is explicit declaration of empty slice, not nil
-		candidates    = getBallots(ctx)
-		found         = -1
-		blockHeight   = blockchain.GetHeight()
-	)
-
-	for i := 0; i < len(candidates); i++ {
-		cnd := candidates[i]
-
-		if blockHeight-cnd.Height > blockDiff {
-			continue
-		}
-
-		if bytesEqual(cnd.ID, id) {
-			voters := cnd.Voters
-
-			for j := range voters {
-				if bytesEqual(voters[j], from) {
-					return len(voters)
-				}
-			}
-
-			voters = append(voters, from)
-			cnd = common.Ballot{ID: id, Voters: voters, Height: blockHeight}
-			found = len(voters)
-		}
-
-		newCandidates = append(newCandidates, cnd)
-	}
-
-	if found < 0 {
-		found = 1
-		voters := [][]byte{from}
-
-		newCandidates = append(newCandidates, common.Ballot{
-			ID:     id,
-			Voters: voters,
-			Height: blockHeight})
-	}
-
-	setSerialized(ctx, voteKey, newCandidates)
-
-	return found
-}
-
-// removeVotes clears ballots of the decision that has been accepted by
-// inner ring nodes.
-func removeVotes(ctx storage.Context, id []byte) {
-	var (
-		newCandidates = []common.Ballot{} // it is explicit declaration of empty slice, not nil
-		candidates    = getBallots(ctx)
-	)
-
-	for i := 0; i < len(candidates); i++ {
-		cnd := candidates[i]
-		if !bytesEqual(cnd.ID, id) {
-			newCandidates = append(newCandidates, cnd)
-		}
-	}
-
-	setSerialized(ctx, voteKey, newCandidates)
-}
-
-// setSerialized serializes data and puts it into contract storage.
-func setSerialized(ctx storage.Context, key interface{}, value interface{}) {
-	data := binary.Serialize(value)
-	storage.Put(ctx, key, data)
-}
-
 // getInnerRingNodes returns deserialized slice of inner ring nodes from storage.
 func getInnerRingNodes(ctx storage.Context, key string) []node {
 	data := storage.Get(ctx, key)
@@ -632,16 +555,6 @@ func getCashedCheques(ctx storage.Context) []cheque {
 	return []cheque{}
 }
 
-// getInnerRingNodes returns deserialized slice of vote ballots.
-func getBallots(ctx storage.Context) []common.Ballot {
-	data := storage.Get(ctx, voteKey)
-	if data != nil {
-		return binary.Deserialize(data.([]byte)).([]common.Ballot)
-	}
-
-	return []common.Ballot{}
-}
-
 // getConfig returns installed neofs configuration value or nil if it is not set.
 func getConfig(ctx storage.Context, key interface{}) interface{} {
 	postfix := key.([]byte)
@@ -662,7 +575,7 @@ func setConfig(ctx storage.Context, key, val interface{}) {
 // that set to false if cheque 'c' is already presented in the slice 'lst'.
 func addCheque(lst []cheque, c cheque) ([]cheque, bool) {
 	for i := 0; i < len(lst); i++ {
-		if bytesEqual(c.id, lst[i].id) {
+		if common.BytesEqual(c.id, lst[i].id) {
 			return nil, false
 		}
 	}
@@ -676,7 +589,7 @@ func addCheque(lst []cheque, c cheque) ([]cheque, bool) {
 // that set to false if node 'n' is already presented in the slice 'lst'.
 func addNode(lst []node, n node) ([]node, bool) {
 	for i := 0; i < len(lst); i++ {
-		if bytesEqual(n.pub, lst[i].pub) {
+		if common.BytesEqual(n.pub, lst[i].pub) {
 			return nil, false
 		}
 	}
@@ -696,7 +609,7 @@ func rmNodeByKey(lst, add []node, k []byte) ([]node, []node, bool) {
 	)
 
 	for i := 0; i < len(lst); i++ {
-		if bytesEqual(k, lst[i].pub) {
+		if common.BytesEqual(k, lst[i].pub) {
 			add = append(add, lst[i])
 			flag = true
 		} else {
@@ -706,9 +619,3 @@ func rmNodeByKey(lst, add []node, k []byte) ([]node, []node, bool) {
 
 	return newLst, add, flag
 }
-
-// bytesEqual compares two slice of bytes by wrapping them into strings,
-// which is necessary with new util.Equal interop behaviour, see neo-go#1176.
-func bytesEqual(a []byte, b []byte) bool {
-	return util.Equals(string(a), string(b))
-}
diff --git a/neofsid/neofsid_contract.go b/neofsid/neofsid_contract.go
index a60a545..c40fb13 100644
--- a/neofsid/neofsid_contract.go
+++ b/neofsid/neofsid_contract.go
@@ -2,12 +2,10 @@ package neofsidcontract
 
 import (
 	"github.com/nspcc-dev/neo-go/pkg/interop/binary"
-	"github.com/nspcc-dev/neo-go/pkg/interop/blockchain"
 	"github.com/nspcc-dev/neo-go/pkg/interop/contract"
 	"github.com/nspcc-dev/neo-go/pkg/interop/crypto"
 	"github.com/nspcc-dev/neo-go/pkg/interop/runtime"
 	"github.com/nspcc-dev/neo-go/pkg/interop/storage"
-	"github.com/nspcc-dev/neo-go/pkg/interop/util"
 	"github.com/nspcc-dev/neofs-contract/common"
 )
 
@@ -22,10 +20,7 @@ type (
 )
 
 const (
-	version   = 1
-	blockDiff = 20 // change base on performance evaluation
-
-	voteKey = "ballots"
+	version = 1
 
 	netmapContractKey    = "netmapScriptHash"
 	containerContractKey = "containerScriptHash"
@@ -88,7 +83,7 @@ addLoop:
 
 		for j := range info.Keys {
 			key := info.Keys[j]
-			if bytesEqual(key, pubKey) {
+			if common.BytesEqual(key, pubKey) {
 				continue addLoop
 			}
 		}
@@ -102,7 +97,7 @@ addLoop:
 		runtime.Log("addKey: processed indirect invoke")
 	} else {
 		id := invokeIDKeys(owner, keys, []byte("add"))
-		n = vote(ctx, id, irKey)
+		n = common.Vote(ctx, id, irKey)
 	}
 
 	if n < threshold {
@@ -110,8 +105,8 @@ addLoop:
 		return true
 	}
 
-	removeVotes(ctx, id)
-	setSerialized(ctx, owner, info)
+	common.RemoveVotes(ctx, id)
+	common.SetSerialized(ctx, owner, info)
 	runtime.Log("addKey: key bound to the owner")
 
 	return true
@@ -133,13 +128,13 @@ func RemoveKey(owner []byte, keys [][]byte) bool {
 
 	id := invokeIDKeys(owner, keys, []byte("remove"))
 
-	n := vote(ctx, id, irKey)
+	n := common.Vote(ctx, id, irKey)
 	if n < threshold {
 		runtime.Log("removeKey: processed invoke from inner ring")
 		return true
 	}
 
-	removeVotes(ctx, id)
+	common.RemoveVotes(ctx, id)
 
 	info := getUserInfo(ctx, owner)
 	var leftKeys [][]byte
@@ -154,7 +149,7 @@ rmLoop:
 				panic("removeKey: incorrect public key")
 			}
 
-			if bytesEqual(key, pubKey) {
+			if common.BytesEqual(key, pubKey) {
 				continue rmLoop
 			}
 		}
@@ -163,7 +158,7 @@ rmLoop:
 	}
 
 	info.Keys = leftKeys
-	setSerialized(ctx, owner, info)
+	common.SetSerialized(ctx, owner, info)
 
 	return true
 }
@@ -191,20 +186,6 @@ func getUserInfo(ctx storage.Context, key interface{}) UserInfo {
 	return UserInfo{Keys: [][]byte{}}
 }
 
-func getBallots(ctx storage.Context) []common.Ballot {
-	data := storage.Get(ctx, voteKey)
-	if data != nil {
-		return binary.Deserialize(data.([]byte)).([]common.Ballot)
-	}
-
-	return []common.Ballot{}
-}
-
-func setSerialized(ctx storage.Context, key interface{}, value interface{}) {
-	data := binary.Serialize(value)
-	storage.Put(ctx, key, data)
-}
-
 func innerRingInvoker(ir []irNode) []byte {
 	for i := 0; i < len(ir); i++ {
 		node := ir[i]
@@ -216,68 +197,6 @@ func innerRingInvoker(ir []irNode) []byte {
 	return nil
 }
 
-func vote(ctx storage.Context, id, from []byte) int {
-	var (
-		newCandidates []common.Ballot
-		candidates    = getBallots(ctx)
-		found         = -1
-		blockHeight   = blockchain.GetHeight()
-	)
-
-	for i := 0; i < len(candidates); i++ {
-		cnd := candidates[i]
-
-		if blockHeight-cnd.Height > blockDiff {
-			continue
-		}
-
-		if bytesEqual(cnd.ID, id) {
-			voters := cnd.Voters
-
-			for j := range voters {
-				if bytesEqual(voters[j], from) {
-					return len(voters)
-				}
-			}
-
-			voters = append(voters, from)
-			cnd = common.Ballot{ID: id, Voters: voters, Height: blockHeight}
-			found = len(voters)
-		}
-
-		newCandidates = append(newCandidates, cnd)
-	}
-
-	if found < 0 {
-		voters := [][]byte{from}
-		newCandidates = append(newCandidates, common.Ballot{
-			ID:     id,
-			Voters: voters,
-			Height: blockHeight})
-		found = 1
-	}
-
-	setSerialized(ctx, voteKey, newCandidates)
-
-	return found
-}
-
-func removeVotes(ctx storage.Context, id []byte) {
-	var (
-		newCandidates []common.Ballot
-		candidates    = getBallots(ctx)
-	)
-
-	for i := 0; i < len(candidates); i++ {
-		cnd := candidates[i]
-		if !bytesEqual(cnd.ID, id) {
-			newCandidates = append(newCandidates, cnd)
-		}
-	}
-
-	setSerialized(ctx, voteKey, newCandidates)
-}
-
 func invokeID(args []interface{}, prefix []byte) []byte {
 	for i := range args {
 		arg := args[i].([]byte)
@@ -296,14 +215,9 @@ func invokeIDKeys(owner []byte, keys [][]byte, prefix []byte) []byte {
 	return crypto.SHA256(prefix)
 }
 
-// neo-go#1176
-func bytesEqual(a []byte, b []byte) bool {
-	return util.Equals(string(a), string(b))
-}
-
 func fromKnownContract(caller []byte) bool {
 	containerContractAddr := storage.Get(ctx, containerContractKey).([]byte)
-	if bytesEqual(caller, containerContractAddr) {
+	if common.BytesEqual(caller, containerContractAddr) {
 		return true
 	}
 
diff --git a/netmap/netmap_contract.go b/netmap/netmap_contract.go
index 5c31794..bc2b6e3 100644
--- a/netmap/netmap_contract.go
+++ b/netmap/netmap_contract.go
@@ -2,12 +2,10 @@ package netmapcontract
 
 import (
 	"github.com/nspcc-dev/neo-go/pkg/interop/binary"
-	"github.com/nspcc-dev/neo-go/pkg/interop/blockchain"
 	"github.com/nspcc-dev/neo-go/pkg/interop/crypto"
 	"github.com/nspcc-dev/neo-go/pkg/interop/iterator"
 	"github.com/nspcc-dev/neo-go/pkg/interop/runtime"
 	"github.com/nspcc-dev/neo-go/pkg/interop/storage"
-	"github.com/nspcc-dev/neo-go/pkg/interop/util"
 	"github.com/nspcc-dev/neofs-contract/common"
 )
 
@@ -34,10 +32,8 @@ type (
 )
 
 const (
-	version   = 1
-	blockDiff = 20 // change base on performance evaluation
+	version = 1
 
-	voteKey       = "ballots"
 	netmapKey     = "netmap"
 	innerRingKey  = "innerring"
 	configuredKey = "initconfig"
@@ -81,16 +77,16 @@ func Init(keys [][]byte) {
 		irList = append(irList, irNode{key: key})
 	}
 
-	setSerialized(ctx, innerRingKey, irList)
+	common.SetSerialized(ctx, innerRingKey, irList)
 
 	// epoch number is a little endian int, it doesn't need to be serialized
 	storage.Put(ctx, snapshotEpoch, 0)
 
 	// simplified: this used for const sysfee in AddPeer method
-	setSerialized(ctx, netmapKey, []netmapNode{})
-	setSerialized(ctx, snapshot0Key, []netmapNode{})
-	setSerialized(ctx, snapshot1Key, []netmapNode{})
-	setSerialized(ctx, voteKey, []common.Ballot{})
+	common.SetSerialized(ctx, netmapKey, []netmapNode{})
+	common.SetSerialized(ctx, snapshot0Key, []netmapNode{})
+	common.SetSerialized(ctx, snapshot1Key, []netmapNode{})
+	common.InitVote(ctx)
 
 	runtime.Log("netmap contract initialized")
 }
@@ -118,11 +114,11 @@ func UpdateInnerRing(keys [][]byte) bool {
 	rawIRList := binary.Serialize(irList)
 	hashIRList := crypto.SHA256(rawIRList)
 
-	n := vote(ctx, hashIRList, irKey)
+	n := common.Vote(ctx, hashIRList, irKey)
 	if n >= threshold {
 		runtime.Log("updateInnerRing: inner ring list updated")
-		setSerialized(ctx, innerRingKey, irList)
-		removeVotes(ctx, hashIRList)
+		common.SetSerialized(ctx, innerRingKey, irList)
+		common.RemoveVotes(ctx, hashIRList)
 	} else {
 		runtime.Log("updateInnerRing: processed invoke from inner ring")
 	}
@@ -152,15 +148,15 @@ func AddPeer(nodeInfo []byte) bool {
 
 	nm := addToNetmap(ctx, candidate)
 
-	n := vote(ctx, hashCandidate, irKey)
+	n := common.Vote(ctx, hashCandidate, irKey)
 	if n >= threshold {
 		if nm == nil {
 			runtime.Log("addPeer: storage node already in the netmap")
 		} else {
-			setSerialized(ctx, netmapKey, nm)
+			common.SetSerialized(ctx, netmapKey, nm)
 			runtime.Log("addPeer: add storage node to the network map")
 		}
-		removeVotes(ctx, hashCandidate)
+		common.RemoveVotes(ctx, hashCandidate)
 	} else {
 		runtime.Log("addPeer: processed invoke from inner ring")
 	}
@@ -190,11 +186,11 @@ func UpdateState(state int, publicKey []byte) bool {
 		newNetmap := removeFromNetmap(ctx, publicKey)
 
 		hashID := invokeID([]interface{}{publicKey}, []byte("delete"))
-		n := vote(ctx, hashID, irKey)
+		n := common.Vote(ctx, hashID, irKey)
 		if n >= threshold {
 			runtime.Log("updateState: remove storage node from the network map")
-			setSerialized(ctx, netmapKey, newNetmap)
-			removeVotes(ctx, hashID)
+			common.SetSerialized(ctx, netmapKey, newNetmap)
+			common.RemoveVotes(ctx, hashID)
 		} else {
 			runtime.Log("updateState: processed invoke from inner ring")
 		}
@@ -224,7 +220,7 @@ func NewEpoch(epochNum int) bool {
 
 	hashID := invokeID([]interface{}{epochNum}, []byte("epoch"))
 
-	n := vote(ctx, hashID, irKey)
+	n := common.Vote(ctx, hashID, irKey)
 	if n >= threshold {
 		runtime.Log("newEpoch: process new epoch")
 
@@ -232,12 +228,12 @@ func NewEpoch(epochNum int) bool {
 		storage.Put(ctx, snapshotEpoch, epochNum)
 
 		// put actual snapshot into previous snapshot
-		setSerialized(ctx, snapshot1Key, data0snapshot)
+		common.SetSerialized(ctx, snapshot1Key, data0snapshot)
 
 		// put netmap into actual snapshot
-		setSerialized(ctx, snapshot0Key, dataOnlineState)
+		common.SetSerialized(ctx, snapshot0Key, dataOnlineState)
 
-		removeVotes(ctx, hashID)
+		common.RemoveVotes(ctx, hashID)
 		runtime.Notify("NewEpoch", epochNum)
 	} else {
 		runtime.Log("newEpoch: processed invoke from inner ring")
@@ -290,10 +286,10 @@ func SetConfig(id, key, val []byte) bool {
 
 	// check unique id of the operation
 	hashID := invokeID([]interface{}{id, key, val}, []byte("config"))
-	n := vote(ctx, hashID, irKey)
+	n := common.Vote(ctx, hashID, irKey)
 
 	if n >= threshold {
-		removeVotes(ctx, hashID)
+		common.RemoveVotes(ctx, hashID)
 		setConfig(ctx, key, val)
 
 		runtime.Log("setConfig: configuration has been updated")
@@ -371,7 +367,7 @@ func addToNetmap(ctx storage.Context, n storageNode) []netmapNode {
 		netmapNode := netmap[i].node.info
 		netmapNodeKey := netmapNode[2:35]
 
-		if bytesEqual(newNodeKey, netmapNodeKey) {
+		if common.BytesEqual(newNodeKey, netmapNodeKey) {
 			return nil
 		}
 	}
@@ -392,7 +388,7 @@ func removeFromNetmap(ctx storage.Context, key []byte) []netmapNode {
 		node := item.node.info
 		publicKey := node[2:35] // offset:2, len:33
 
-		if !bytesEqual(publicKey, key) {
+		if !common.BytesEqual(publicKey, key) {
 			newNetmap = append(newNetmap, item)
 		}
 	}
@@ -416,68 +412,6 @@ func filterNetmap(ctx storage.Context, st nodeState) []storageNode {
 	return result
 }
 
-func vote(ctx storage.Context, id, from []byte) int {
-	var (
-		newCandidates []common.Ballot
-		candidates    = getBallots(ctx)
-		found         = -1
-		blockHeight   = blockchain.GetHeight()
-	)
-
-	for i := 0; i < len(candidates); i++ {
-		cnd := candidates[i]
-
-		if blockHeight-cnd.Height > blockDiff {
-			continue
-		}
-
-		if bytesEqual(cnd.ID, id) {
-			voters := cnd.Voters
-
-			for j := range voters {
-				if bytesEqual(voters[j], from) {
-					return len(voters)
-				}
-			}
-
-			voters = append(voters, from)
-			cnd = common.Ballot{ID: id, Voters: voters, Height: blockHeight}
-			found = len(voters)
-		}
-
-		newCandidates = append(newCandidates, cnd)
-	}
-
-	if found < 0 {
-		voters := [][]byte{from}
-		newCandidates = append(newCandidates, common.Ballot{
-			ID:     id,
-			Voters: voters,
-			Height: blockHeight})
-		found = 1
-	}
-
-	setSerialized(ctx, voteKey, newCandidates)
-
-	return found
-}
-
-func removeVotes(ctx storage.Context, id []byte) {
-	var (
-		newCandidates []common.Ballot
-		candidates    = getBallots(ctx)
-	)
-
-	for i := 0; i < len(candidates); i++ {
-		cnd := candidates[i]
-		if !bytesEqual(cnd.ID, id) {
-			newCandidates = append(newCandidates, cnd)
-		}
-	}
-
-	setSerialized(ctx, voteKey, newCandidates)
-}
-
 func getIRNodes(ctx storage.Context) []irNode {
 	data := storage.Get(ctx, innerRingKey)
 	if data != nil {
@@ -505,20 +439,6 @@ func getSnapshot(ctx storage.Context, key string) []storageNode {
 	return []storageNode{}
 }
 
-func getBallots(ctx storage.Context) []common.Ballot {
-	data := storage.Get(ctx, voteKey)
-	if data != nil {
-		return binary.Deserialize(data.([]byte)).([]common.Ballot)
-	}
-
-	return []common.Ballot{}
-}
-
-func setSerialized(ctx storage.Context, key interface{}, value interface{}) {
-	data := binary.Serialize(value)
-	storage.Put(ctx, key, data)
-}
-
 func getConfig(ctx storage.Context, key interface{}) interface{} {
 	postfix := key.([]byte)
 	storageKey := append(configPrefix, postfix...)
@@ -541,8 +461,3 @@ func invokeID(args []interface{}, prefix []byte) []byte {
 
 	return crypto.SHA256(prefix)
 }
-
-// neo-go#1176
-func bytesEqual(a []byte, b []byte) bool {
-	return util.Equals(string(a), string(b))
-}
diff --git a/reputation/reputation_contract.go b/reputation/reputation_contract.go
index 2a62cf1..5f5242c 100644
--- a/reputation/reputation_contract.go
+++ b/reputation/reputation_contract.go
@@ -4,6 +4,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/interop/binary"
 	"github.com/nspcc-dev/neo-go/pkg/interop/runtime"
 	"github.com/nspcc-dev/neo-go/pkg/interop/storage"
+	"github.com/nspcc-dev/neofs-contract/common"
 )
 
 const version = 1
@@ -64,7 +65,7 @@ func Put(manager, epoch, typ []byte, newTrustList [][]byte) bool {
 		}
 	}
 
-	setSerialized(ctx, key, trustList)
+	common.SetSerialized(ctx, key, trustList)
 
 	runtime.Log("trust list was successfully updated")
 
@@ -85,8 +86,3 @@ func getList(ctx storage.Context, key interface{}) [][]byte {
 
 	return [][]byte{}
 }
-
-func setSerialized(ctx storage.Context, key interface{}, value interface{}) {
-	data := binary.Serialize(value)
-	storage.Put(ctx, key, data)
-}