diff --git a/alphabet/alphabet_contract.go b/alphabet/alphabet_contract.go
index e31ff2a..15b7e7c 100644
--- a/alphabet/alphabet_contract.go
+++ b/alphabet/alphabet_contract.go
@@ -10,12 +10,6 @@ import (
 	"github.com/nspcc-dev/neofs-contract/common"
 )
 
-type (
-	irNode struct {
-		key []byte
-	}
-)
-
 const (
 	// native gas token script hash
 	gasHash = "\xfb\xed\xfe\x2e\xd2\x22\x65\x92\xb6\x48\xc4\xda\x97\xb9\xc9\xcd\x5d\xc1\xa6\xa6"
@@ -84,9 +78,9 @@ func balance(hash string, addr []byte) int {
 	return balance.(int)
 }
 
-func irList() []irNode {
+func irList() []common.IRNode {
 	netmapContractAddr := storage.Get(ctx, netmapKey).([]byte)
-	return contract.Call(netmapContractAddr, "innerRingList").([]irNode)
+	return contract.Call(netmapContractAddr, "innerRingList").([]common.IRNode)
 }
 
 func currentEpoch() int {
@@ -106,7 +100,7 @@ func total() int {
 	return storage.Get(ctx, totalKey).(int)
 }
 
-func checkPermission(ir []irNode) bool {
+func checkPermission(ir []common.IRNode) bool {
 	index := index() // read from contract memory
 
 	if len(ir) <= index {
@@ -114,24 +108,7 @@ func checkPermission(ir []irNode) bool {
 	}
 
 	node := ir[index]
-	return runtime.CheckWitness(node.key)
-}
-
-func innerRingInvoker(ir []irNode) []byte {
-	amountOfContracts := total() // read from contract memory
-
-	for i := 0; i < len(ir); i++ {
-		if i >= amountOfContracts {
-			return nil
-		}
-
-		node := ir[i]
-		if runtime.CheckWitness(node.key) {
-			return node.key
-		}
-	}
-
-	return nil
+	return runtime.CheckWitness(node.PublicKey)
 }
 
 func Emit() bool {
@@ -155,7 +132,7 @@ func Emit() bool {
 
 	for i := range innerRingKeys {
 		node := innerRingKeys[i]
-		address := contract.CreateStandardAccount(node.key)
+		address := contract.CreateStandardAccount(node.PublicKey)
 
 		_ = contract.Call([]byte(gasHash), "transfer", contractHash, address, gasPerNode, nil)
 	}
@@ -170,7 +147,7 @@ func Vote(epoch int, candidates [][]byte) {
 	index := index()
 	name := name()
 
-	key := innerRingInvoker(innerRingKeys)
+	key := common.InnerRingInvoker(innerRingKeys)
 	if len(key) == 0 {
 		panic("invalid invoker")
 	}
diff --git a/balance/balance_contract.go b/balance/balance_contract.go
index ac7b1ce..c4c515f 100644
--- a/balance/balance_contract.go
+++ b/balance/balance_contract.go
@@ -11,10 +11,6 @@ import (
 )
 
 type (
-	irNode struct {
-		key []byte
-	}
-
 	// Token holds all token info.
 	Token struct {
 		// Ticker symbol
@@ -114,10 +110,10 @@ func TransferX(from, to interop.Hash160, amount int, details []byte) bool {
 	)
 
 	netmapContractAddr := storage.Get(ctx, netmapContractKey).([]byte)
-	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]irNode)
+	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]common.IRNode)
 	threshold := len(innerRing)/3*2 + 1
 
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		panic("transferX: this method must be invoked from inner ring")
 	}
@@ -150,10 +146,10 @@ func TransferX(from, to interop.Hash160, amount int, details []byte) bool {
 
 func Lock(txID []byte, from, to interop.Hash160, amount, until int) bool {
 	netmapContractAddr := storage.Get(ctx, netmapContractKey).([]byte)
-	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]irNode)
+	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]common.IRNode)
 	threshold := len(innerRing)/3*2 + 1
 
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		panic("lock: this method must be invoked from inner ring")
 	}
@@ -188,10 +184,10 @@ func Lock(txID []byte, from, to interop.Hash160, amount, until int) bool {
 
 func NewEpoch(epochNum int) bool {
 	netmapContractAddr := storage.Get(ctx, netmapContractKey).([]byte)
-	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]irNode)
+	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]common.IRNode)
 	threshold := len(innerRing)/3*2 + 1
 
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		panic("epochNum: this method must be invoked from inner ring")
 	}
@@ -227,10 +223,10 @@ func NewEpoch(epochNum int) bool {
 
 func Mint(to interop.Hash160, amount int, details []byte) bool {
 	netmapContractAddr := storage.Get(ctx, netmapContractKey).([]byte)
-	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]irNode)
+	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]common.IRNode)
 	threshold := len(innerRing)/3*2 + 1
 
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		panic("burn: this method must be invoked from inner ring")
 	}
@@ -258,10 +254,10 @@ func Mint(to interop.Hash160, amount int, details []byte) bool {
 
 func Burn(from interop.Hash160, amount int, details []byte) bool {
 	netmapContractAddr := storage.Get(ctx, netmapContractKey).([]byte)
-	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]irNode)
+	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]common.IRNode)
 	threshold := len(innerRing)/3*2 + 1
 
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		panic("burn: this method must be invoked from inner ring")
 	}
@@ -381,17 +377,6 @@ func isUsableAddress(addr interop.Hash160) bool {
 	return false
 }
 
-func innerRingInvoker(ir []irNode) []byte {
-	for i := 0; i < len(ir); i++ {
-		node := ir[i]
-		if runtime.CheckWitness(node.key) {
-			return node.key
-		}
-	}
-
-	return nil
-}
-
 func getAccount(ctx storage.Context, key interface{}) Account {
 	data := storage.Get(ctx, key)
 	if data != nil {
diff --git a/common/invoke.go b/common/invoke.go
index 6dfe0fd..7369193 100644
--- a/common/invoke.go
+++ b/common/invoke.go
@@ -1,6 +1,9 @@
 package common
 
-import "github.com/nspcc-dev/neo-go/pkg/interop/crypto"
+import (
+	"github.com/nspcc-dev/neo-go/pkg/interop/crypto"
+	"github.com/nspcc-dev/neo-go/pkg/interop/runtime"
+)
 
 func InvokeID(args []interface{}, prefix []byte) []byte {
 	for i := range args {
@@ -10,3 +13,19 @@ func InvokeID(args []interface{}, prefix []byte) []byte {
 
 	return crypto.SHA256(prefix)
 }
+
+type IRNode struct {
+	PublicKey []byte
+}
+
+// InnerRingInvoker returns public key of inner ring node that invoked contract.
+func InnerRingInvoker(ir []IRNode) []byte {
+	for i := 0; i < len(ir); i++ {
+		node := ir[i]
+		if runtime.CheckWitness(node.PublicKey) {
+			return node.PublicKey
+		}
+	}
+
+	return nil
+}
diff --git a/container/container_contract.go b/container/container_contract.go
index 186bc63..58abaa5 100644
--- a/container/container_contract.go
+++ b/container/container_contract.go
@@ -12,10 +12,6 @@ import (
 )
 
 type (
-	irNode struct {
-		key []byte
-	}
-
 	storageNode struct {
 		info []byte
 	}
@@ -87,7 +83,7 @@ func Init(addrNetmap, addrBalance, addrID []byte) {
 
 func Put(container, signature, publicKey []byte) bool {
 	netmapContractAddr := storage.Get(ctx, netmapContractKey).([]byte)
-	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]irNode)
+	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]common.IRNode)
 	threshold := len(innerRing)/3*2 + 1
 
 	offset := int(container[1])
@@ -98,7 +94,7 @@ func Put(container, signature, publicKey []byte) bool {
 
 	// If invoked from storage node, ignore it.
 	// Inner ring will find tx, validate it and send it again.
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		// check provided key
 		if !isSignedByOwnerKey(container, signature, ownerID, publicKey) {
@@ -126,7 +122,7 @@ func Put(container, signature, publicKey []byte) bool {
 
 		for i := 0; i < len(innerRing); i++ {
 			node := innerRing[i]
-			to := contract.CreateStandardAccount(node.key)
+			to := contract.CreateStandardAccount(node.PublicKey)
 
 			tx := contract.Call(balanceContractAddr, "transferX",
 				from,
@@ -154,7 +150,7 @@ func Put(container, signature, publicKey []byte) bool {
 
 func Delete(containerID, signature []byte) bool {
 	netmapContractAddr := storage.Get(ctx, netmapContractKey).([]byte)
-	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]irNode)
+	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]common.IRNode)
 	threshold := len(innerRing)/3*2 + 1
 
 	ownerID := getOwnerByID(ctx, containerID)
@@ -164,7 +160,7 @@ func Delete(containerID, signature []byte) bool {
 
 	// If invoked from storage node, ignore it.
 	// Inner ring will find tx, validate it and send it again.
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		// check provided key
 		neofsIDContractAddr := storage.Get(ctx, neofsIDContractKey).([]byte)
@@ -341,10 +337,10 @@ func ListContainerSizes(epoch int) [][]byte {
 
 func ProcessEpoch(epochNum int) {
 	netmapContractAddr := storage.Get(ctx, netmapContractKey).([]byte)
-	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]irNode)
+	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]common.IRNode)
 	threshold := len(innerRing)/3*2 + 1
 
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		panic("processEpoch: this method must be invoked from inner ring")
 	}
@@ -365,10 +361,10 @@ func ProcessEpoch(epochNum int) {
 
 func StartContainerEstimation(epoch int) bool {
 	netmapContractAddr := storage.Get(ctx, netmapContractKey).([]byte)
-	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]irNode)
+	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]common.IRNode)
 	threshold := len(innerRing)/3*2 + 1
 
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		panic("startEstimation: only inner ring nodes can invoke this")
 	}
@@ -389,10 +385,10 @@ func StartContainerEstimation(epoch int) bool {
 
 func StopContainerEstimation(epoch int) bool {
 	netmapContractAddr := storage.Get(ctx, netmapContractKey).([]byte)
-	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]irNode)
+	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]common.IRNode)
 	threshold := len(innerRing)/3*2 + 1
 
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		panic("stopEstimation: only inner ring nodes can invoke this")
 	}
@@ -472,17 +468,6 @@ func remove(ctx storage.Context, key interface{}, value []byte) int {
 	return ln
 }
 
-func innerRingInvoker(ir []irNode) []byte {
-	for i := 0; i < len(ir); i++ {
-		node := ir[i]
-		if runtime.CheckWitness(node.key) {
-			return node.key
-		}
-	}
-
-	return nil
-}
-
 func getList(ctx storage.Context, key interface{}) [][]byte {
 	data := storage.Get(ctx, key)
 	if data != nil {
diff --git a/neofs/neofs_contract.go b/neofs/neofs_contract.go
index e2178a7..3eb9569 100644
--- a/neofs/neofs_contract.go
+++ b/neofs/neofs_contract.go
@@ -43,10 +43,6 @@ import (
 )
 
 type (
-	node struct {
-		pub []byte
-	}
-
 	cheque struct {
 		id []byte
 	}
@@ -102,7 +98,7 @@ func Init(args [][]byte) bool {
 		panic("neofs: contract already deployed")
 	}
 
-	var irList []node
+	var irList []common.IRNode
 
 	if len(args) < 3 {
 		panic("neofs: at least three inner ring keys must be provided")
@@ -113,13 +109,13 @@ func Init(args [][]byte) bool {
 		if len(pub) != publicKeySize {
 			panic("neofs: incorrect public key length")
 		}
-		irList = append(irList, node{pub: pub})
+		irList = append(irList, common.IRNode{PublicKey: pub})
 	}
 
 	// initialize all storage slices
 	common.SetSerialized(ctx, innerRingKey, irList)
 	common.InitVote(ctx)
-	common.SetSerialized(ctx, candidatesKey, []node{})
+	common.SetSerialized(ctx, candidatesKey, []common.IRNode{})
 	common.SetSerialized(ctx, cashedChequesKey, []cheque{})
 
 	runtime.Log("neofs: contract initialized")
@@ -128,12 +124,12 @@ func Init(args [][]byte) bool {
 }
 
 // InnerRingList returns array of inner ring node keys.
-func InnerRingList() []node {
+func InnerRingList() []common.IRNode {
 	return getInnerRingNodes(ctx, innerRingKey)
 }
 
 // InnerRingCandidates returns array of inner ring candidate node keys.
-func InnerRingCandidates() []node {
+func InnerRingCandidates() []common.IRNode {
 	return getInnerRingNodes(ctx, candidatesKey)
 }
 
@@ -143,12 +139,12 @@ func InnerRingCandidateRemove(key []byte) bool {
 		panic("irCandidateRemove: you should be the owner of the public key")
 	}
 
-	nodes := []node{} // it is explicit declaration of empty slice, not nil
+	nodes := []common.IRNode{} // it is explicit declaration of empty slice, not nil
 	candidates := getInnerRingNodes(ctx, candidatesKey)
 
 	for i := range candidates {
 		c := candidates[i]
-		if !common.BytesEqual(c.pub, key) {
+		if !common.BytesEqual(c.PublicKey, key) {
 			nodes = append(nodes, c)
 		} else {
 			runtime.Log("irCandidateRemove: candidate has been removed")
@@ -166,7 +162,7 @@ func InnerRingCandidateAdd(key []byte) bool {
 		panic("irCandidateAdd: you should be the owner of the public key")
 	}
 
-	c := node{pub: key}
+	c := common.IRNode{PublicKey: key}
 	candidates := getInnerRingNodes(ctx, candidatesKey)
 
 	list, ok := addNode(candidates, c)
@@ -274,7 +270,7 @@ func Cheque(id, user []byte, amount int, lockAcc []byte) bool {
 	cashedCheques := getCashedCheques(ctx)
 	hashID := crypto.SHA256(id)
 
-	irKey := innerRingInvoker(irList)
+	irKey := common.InnerRingInvoker(irList)
 	if len(irKey) == 0 {
 		panic("cheque: invoked by non inner ring node")
 	}
@@ -353,7 +349,7 @@ func InnerRingUpdate(chequeID []byte, args [][]byte) bool {
 	irList := getInnerRingNodes(ctx, innerRingKey)
 	threshold := len(irList)/3*2 + 1
 
-	irKey := innerRingInvoker(irList)
+	irKey := common.InnerRingInvoker(irList)
 	if len(irKey) == 0 {
 		panic("innerRingUpdate: invoked by non inner ring node")
 	}
@@ -369,7 +365,7 @@ func InnerRingUpdate(chequeID []byte, args [][]byte) bool {
 
 	oldNodes := 0
 	candidates := getInnerRingNodes(ctx, candidatesKey)
-	newIR := []node{}
+	newIR := []common.IRNode{}
 
 loop:
 	for i := 0; i < len(args); i++ {
@@ -381,7 +377,7 @@ loop:
 		// find key in actual inner ring list
 		for j := 0; j < len(irList); j++ {
 			n := irList[j]
-			if common.BytesEqual(n.pub, key) {
+			if common.BytesEqual(n.PublicKey, key) {
 				newIR = append(newIR, n)
 				oldNodes++
 
@@ -427,7 +423,7 @@ func IsInnerRing(key []byte) bool {
 	for i := range irList {
 		node := irList[i]
 
-		if common.BytesEqual(node.pub, key) {
+		if common.BytesEqual(node.PublicKey, key) {
 			return true
 		}
 	}
@@ -446,7 +442,7 @@ func SetConfig(id, key, val []byte) bool {
 	irList := getInnerRingNodes(ctx, innerRingKey)
 	threshold := len(irList)/3*2 + 1
 
-	irKey := innerRingInvoker(irList)
+	irKey := common.InnerRingInvoker(irList)
 	if len(irKey) == 0 {
 		panic("setConfig: invoked by non inner ring node")
 	}
@@ -523,26 +519,14 @@ func Version() int {
 	return version
 }
 
-// innerRingInvoker returns public key of inner ring node that invoked contract.
-func innerRingInvoker(ir []node) []byte {
-	for i := 0; i < len(ir); i++ {
-		node := ir[i]
-		if runtime.CheckWitness(node.pub) {
-			return node.pub
-		}
-	}
-
-	return nil
-}
-
 // getInnerRingNodes returns deserialized slice of inner ring nodes from storage.
-func getInnerRingNodes(ctx storage.Context, key string) []node {
+func getInnerRingNodes(ctx storage.Context, key string) []common.IRNode {
 	data := storage.Get(ctx, key)
 	if data != nil {
-		return binary.Deserialize(data.([]byte)).([]node)
+		return binary.Deserialize(data.([]byte)).([]common.IRNode)
 	}
 
-	return []node{}
+	return []common.IRNode{}
 }
 
 // getInnerRingNodes returns deserialized slice of used cheques.
@@ -587,9 +571,9 @@ func addCheque(lst []cheque, c cheque) ([]cheque, bool) {
 
 // addNode returns slice of nodes with appended node 'n' and bool flag
 // that set to false if node 'n' is already presented in the slice 'lst'.
-func addNode(lst []node, n node) ([]node, bool) {
+func addNode(lst []common.IRNode, n common.IRNode) ([]common.IRNode, bool) {
 	for i := 0; i < len(lst); i++ {
-		if common.BytesEqual(n.pub, lst[i].pub) {
+		if common.BytesEqual(n.PublicKey, lst[i].PublicKey) {
 			return nil, false
 		}
 	}
@@ -602,14 +586,14 @@ func addNode(lst []node, n node) ([]node, bool) {
 // rmNodeByKey returns slice of nodes without node with key 'k',
 // slices of nodes 'add' with node with key 'k' and bool flag,
 // that set to false if node with a key 'k' does not exists in the slice 'lst'.
-func rmNodeByKey(lst, add []node, k []byte) ([]node, []node, bool) {
+func rmNodeByKey(lst, add []common.IRNode, k []byte) ([]common.IRNode, []common.IRNode, bool) {
 	var (
 		flag   bool
-		newLst = []node{} // it is explicit declaration of empty slice, not nil
+		newLst = []common.IRNode{} // it is explicit declaration of empty slice, not nil
 	)
 
 	for i := 0; i < len(lst); i++ {
-		if common.BytesEqual(k, lst[i].pub) {
+		if common.BytesEqual(k, lst[i].PublicKey) {
 			add = append(add, lst[i])
 			flag = true
 		} else {
diff --git a/neofsid/neofsid_contract.go b/neofsid/neofsid_contract.go
index c12e84f..6088c85 100644
--- a/neofsid/neofsid_contract.go
+++ b/neofsid/neofsid_contract.go
@@ -10,10 +10,6 @@ import (
 )
 
 type (
-	irNode struct {
-		key []byte
-	}
-
 	UserInfo struct {
 		Keys [][]byte
 	}
@@ -64,10 +60,10 @@ func AddKey(owner []byte, keys [][]byte) bool {
 	}
 
 	netmapContractAddr := storage.Get(ctx, netmapContractKey).([]byte)
-	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]irNode)
+	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]common.IRNode)
 	threshold := len(innerRing)/3*2 + 1
 
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		panic("addKey: invocation from non inner ring node")
 	}
@@ -118,10 +114,10 @@ func RemoveKey(owner []byte, keys [][]byte) bool {
 	}
 
 	netmapContractAddr := storage.Get(ctx, netmapContractKey).([]byte)
-	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]irNode)
+	innerRing := contract.Call(netmapContractAddr, "innerRingList").([]common.IRNode)
 	threshold := len(innerRing)/3*2 + 1
 
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		panic("removeKey: invocation from non inner ring node")
 	}
@@ -186,17 +182,6 @@ func getUserInfo(ctx storage.Context, key interface{}) UserInfo {
 	return UserInfo{Keys: [][]byte{}}
 }
 
-func innerRingInvoker(ir []irNode) []byte {
-	for i := 0; i < len(ir); i++ {
-		node := ir[i]
-		if runtime.CheckWitness(node.key) {
-			return node.key
-		}
-	}
-
-	return nil
-}
-
 func invokeIDKeys(owner []byte, keys [][]byte, prefix []byte) []byte {
 	prefix = append(prefix, owner...)
 	for i := range keys {
diff --git a/netmap/netmap_contract.go b/netmap/netmap_contract.go
index 10e1f4e..65ac7af 100644
--- a/netmap/netmap_contract.go
+++ b/netmap/netmap_contract.go
@@ -10,10 +10,6 @@ import (
 )
 
 type (
-	irNode struct {
-		key []byte
-	}
-
 	storageNode struct {
 		info []byte
 	}
@@ -70,11 +66,11 @@ func Init(keys [][]byte) {
 		panic("netmap: contract already initialized")
 	}
 
-	var irList []irNode
+	var irList []common.IRNode
 
 	for i := 0; i < len(keys); i++ {
 		key := keys[i]
-		irList = append(irList, irNode{key: key})
+		irList = append(irList, common.IRNode{PublicKey: key})
 	}
 
 	common.SetSerialized(ctx, innerRingKey, irList)
@@ -91,7 +87,7 @@ func Init(keys [][]byte) {
 	runtime.Log("netmap contract initialized")
 }
 
-func InnerRingList() []irNode {
+func InnerRingList() []common.IRNode {
 	return getIRNodes(ctx)
 }
 
@@ -99,16 +95,16 @@ func UpdateInnerRing(keys [][]byte) bool {
 	innerRing := getIRNodes(ctx)
 	threshold := len(innerRing)/3*2 + 1
 
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		panic("updateInnerRing: this method must be invoked by inner ring nodes")
 	}
 
-	var irList []irNode
+	var irList []common.IRNode
 
 	for i := 0; i < len(keys); i++ {
 		key := keys[i]
-		irList = append(irList, irNode{key: key})
+		irList = append(irList, common.IRNode{PublicKey: key})
 	}
 
 	rawIRList := binary.Serialize(irList)
@@ -130,7 +126,7 @@ func AddPeer(nodeInfo []byte) bool {
 	innerRing := getIRNodes(ctx)
 	threshold := len(innerRing)/3*2 + 1
 
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		publicKey := nodeInfo[2:35] // offset:2, len:33
 		if !runtime.CheckWitness(publicKey) {
@@ -172,7 +168,7 @@ func UpdateState(state int, publicKey []byte) bool {
 	innerRing := getIRNodes(ctx)
 	threshold := len(innerRing)/3*2 + 1
 
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		if !runtime.CheckWitness(publicKey) {
 			panic("updateState: witness check failed")
@@ -205,7 +201,7 @@ func NewEpoch(epochNum int) bool {
 	innerRing := getIRNodes(ctx)
 	threshold := len(innerRing)/3*2 + 1
 
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		panic("newEpoch: this method must be invoked by inner ring nodes")
 	}
@@ -279,7 +275,7 @@ func SetConfig(id, key, val []byte) bool {
 	innerRing := getIRNodes(ctx)
 	threshold := len(innerRing)/3*2 + 1
 
-	irKey := innerRingInvoker(innerRing)
+	irKey := common.InnerRingInvoker(innerRing)
 	if len(irKey) == 0 {
 		panic("setConfig: invoked by non inner ring node")
 	}
@@ -340,17 +336,6 @@ func Version() int {
 	return version
 }
 
-func innerRingInvoker(ir []irNode) []byte {
-	for i := 0; i < len(ir); i++ {
-		node := ir[i]
-		if runtime.CheckWitness(node.key) {
-			return node.key
-		}
-	}
-
-	return nil
-}
-
 func addToNetmap(ctx storage.Context, n storageNode) []netmapNode {
 	var (
 		newNode    = n.info
@@ -412,13 +397,13 @@ func filterNetmap(ctx storage.Context, st nodeState) []storageNode {
 	return result
 }
 
-func getIRNodes(ctx storage.Context) []irNode {
+func getIRNodes(ctx storage.Context) []common.IRNode {
 	data := storage.Get(ctx, innerRingKey)
 	if data != nil {
-		return binary.Deserialize(data.([]byte)).([]irNode)
+		return binary.Deserialize(data.([]byte)).([]common.IRNode)
 	}
 
-	return []irNode{}
+	return []common.IRNode{}
 }
 
 func getNetmapNodes(ctx storage.Context) []netmapNode {