diff --git a/common/uuid/uuid.go b/common/uuid/uuid.go
index 9ac34086..56a7f9fc 100644
--- a/common/uuid/uuid.go
+++ b/common/uuid/uuid.go
@@ -1,6 +1,8 @@
 package uuid
 
 import (
+	"bytes"
+	"crypto/md5"
 	"crypto/rand"
 	"encoding/hex"
 	"errors"
@@ -22,7 +24,30 @@ func (this *UUID) String() string {
 }
 
 func (this *UUID) Bytes() []byte {
-	return this.byteValue[:]
+	return this.byteValue
+}
+
+func (this *UUID) Equals(another *UUID) bool {
+	if this == nil && another == nil {
+		return true
+	}
+	if this == nil || another == nil {
+		return false
+	}
+	return bytes.Equal(this.Bytes(), another.Bytes())
+}
+
+// Next generates a deterministic random UUID based on this UUID.
+func (this *UUID) Next() *UUID {
+	md5hash := md5.New()
+	md5hash.Write(this.Bytes())
+	md5hash.Write([]byte("16167dc8-16b6-4e6d-b8bb-65dd68113a81"))
+	for {
+		newid, _ := ParseBytes(md5hash.Sum(nil))
+		if !newid.Equals(this) {
+			return newid
+		}
+	}
 }
 
 func bytesToString(bytes []byte) string {
diff --git a/proxy/vmess/id.go b/proxy/vmess/id.go
index dd656862..d40f5b7e 100644
--- a/proxy/vmess/id.go
+++ b/proxy/vmess/id.go
@@ -29,6 +29,10 @@ func (this *ID) String() string {
 	return this.uuid.String()
 }
 
+func (this *ID) UUID() *uuid.UUID {
+	return this.uuid
+}
+
 func NewID(uuid *uuid.UUID) *ID {
 	md5hash := md5.New()
 	md5hash.Write(uuid.Bytes())
diff --git a/proxy/vmess/inbound/inbound.go b/proxy/vmess/inbound/inbound.go
index 457fb035..39f1a41e 100644
--- a/proxy/vmess/inbound/inbound.go
+++ b/proxy/vmess/inbound/inbound.go
@@ -45,6 +45,10 @@ func (this *VMessInboundHandler) Close() {
 	}
 }
 
+func (this *VMessInboundHandler) AddUser(user vmess.User) {
+
+}
+
 func (this *VMessInboundHandler) Listen(port v2net.Port) error {
 	listener, err := net.ListenTCP("tcp", &net.TCPAddr{
 		IP:   []byte{0, 0, 0, 0},
diff --git a/proxy/vmess/json/user.go b/proxy/vmess/json/user.go
index 397a9224..e4903bc8 100644
--- a/proxy/vmess/json/user.go
+++ b/proxy/vmess/json/user.go
@@ -2,6 +2,7 @@ package json
 
 import (
 	"encoding/json"
+	"math/rand"
 
 	"github.com/v2ray/v2ray-core/common/uuid"
 	"github.com/v2ray/v2ray-core/proxy/vmess"
@@ -12,13 +13,15 @@ type ConfigUser struct {
 	Id         *vmess.ID
 	Email      string
 	LevelValue vmess.UserLevel
+	AlterIds   []*vmess.ID
 }
 
 func (u *ConfigUser) UnmarshalJSON(data []byte) error {
 	type rawUser struct {
-		IdString    string `json:"id"`
-		EmailString string `json:"email"`
-		LevelInt    int    `json:"level"`
+		IdString     string `json:"id"`
+		EmailString  string `json:"email"`
+		LevelInt     int    `json:"level"`
+		AlterIdCount int    `json:"alterId"`
 	}
 	var rawUserValue rawUser
 	if err := json.Unmarshal(data, &rawUserValue); err != nil {
@@ -31,6 +34,18 @@ func (u *ConfigUser) UnmarshalJSON(data []byte) error {
 	u.Id = vmess.NewID(id)
 	u.Email = rawUserValue.EmailString
 	u.LevelValue = vmess.UserLevel(rawUserValue.LevelInt)
+
+	if rawUserValue.AlterIdCount > 0 {
+		prevId := u.Id.UUID()
+		// TODO: check duplicate
+		u.AlterIds = make([]*vmess.ID, rawUserValue.AlterIdCount)
+		for idx, _ := range u.AlterIds {
+			newid := prevId.Next()
+			u.AlterIds[idx] = vmess.NewID(newid)
+			prevId = newid
+		}
+	}
+
 	return nil
 }
 
@@ -41,3 +56,18 @@ func (u *ConfigUser) ID() *vmess.ID {
 func (this *ConfigUser) Level() vmess.UserLevel {
 	return this.LevelValue
 }
+
+func (this *ConfigUser) AlterIDs() []*vmess.ID {
+	return this.AlterIds
+}
+
+func (this *ConfigUser) AnyValidID() *vmess.ID {
+	if len(this.AlterIds) == 0 {
+		return this.ID()
+	}
+	if len(this.AlterIds) == 1 {
+		return this.AlterIds[0]
+	}
+	idIdx := rand.Intn(len(this.AlterIds))
+	return this.AlterIds[idIdx]
+}
diff --git a/proxy/vmess/protocol/user/testing/mocks/static_userset.go b/proxy/vmess/protocol/user/testing/mocks/static_userset.go
index 558295c2..6edec2ef 100644
--- a/proxy/vmess/protocol/user/testing/mocks/static_userset.go
+++ b/proxy/vmess/protocol/user/testing/mocks/static_userset.go
@@ -17,6 +17,14 @@ func (this *StaticUser) Level() vmess.UserLevel {
 	return vmess.UserLevelUntrusted
 }
 
+func (this *StaticUser) AlterIDs() []*vmess.ID {
+	return nil
+}
+
+func (this *StaticUser) AnyValidID() *vmess.ID {
+	return this.id
+}
+
 type StaticUserSet struct {
 }
 
diff --git a/proxy/vmess/protocol/user/userset.go b/proxy/vmess/protocol/user/userset.go
index 69aaf4e3..50207458 100644
--- a/proxy/vmess/protocol/user/userset.go
+++ b/proxy/vmess/protocol/user/userset.go
@@ -69,6 +69,9 @@ func (us *TimedUserSet) updateUserHash(tick <-chan time.Time) {
 		nowSec := now.Unix() + cacheDurationSec
 		for idx, user := range us.validUsers {
 			us.generateNewHashes(lastSec, nowSec, idx, user.ID())
+			for _, alterid := range user.AlterIDs() {
+				us.generateNewHashes(lastSec, nowSec, idx, alterid)
+			}
 		}
 		lastSec = nowSec
 	}
@@ -82,6 +85,9 @@ func (us *TimedUserSet) AddUser(user vmess.User) error {
 	nowSec := time.Now().Unix()
 	lastSec := nowSec - cacheDurationSec
 	us.generateNewHashes(lastSec, nowSec+cacheDurationSec, idx, id)
+	for _, alterid := range user.AlterIDs() {
+		us.generateNewHashes(lastSec, nowSec+cacheDurationSec, idx, alterid)
+	}
 
 	return nil
 }
diff --git a/proxy/vmess/protocol/vmess.go b/proxy/vmess/protocol/vmess.go
index 65f83259..63a2acd3 100644
--- a/proxy/vmess/protocol/vmess.go
+++ b/proxy/vmess/protocol/vmess.go
@@ -175,7 +175,7 @@ func (this *VMessRequest) ToBytes(idHash user.CounterHash, randomRangeInt64 user
 	}
 
 	counter := randomRangeInt64(time.Now().Unix(), 30)
-	hash := idHash.Hash(this.User.ID().Bytes(), counter)
+	hash := idHash.Hash(this.User.AnyValidID().Bytes(), counter)
 
 	buffer.Append(hash)
 
diff --git a/proxy/vmess/user.go b/proxy/vmess/user.go
index fe64339c..06a8857c 100644
--- a/proxy/vmess/user.go
+++ b/proxy/vmess/user.go
@@ -1,9 +1,5 @@
 package vmess
 
-import (
-	"time"
-)
-
 type UserLevel int
 
 const (
@@ -13,12 +9,9 @@ const (
 
 type User interface {
 	ID() *ID
+	AlterIDs() []*ID
 	Level() UserLevel
-}
-
-type SecondaryID interface {
-	ID() *ID
-	ValidUntil() time.Time
+	AnyValidID() *ID
 }
 
 type UserSettings struct {
diff --git a/testing/scenarios/data/test_1_client.json b/testing/scenarios/data/test_1_client.json
index 6c26e904..c51fc14a 100644
--- a/testing/scenarios/data/test_1_client.json
+++ b/testing/scenarios/data/test_1_client.json
@@ -16,7 +16,10 @@
           "address": "127.0.0.1",
           "port": 50001,
           "users": [
-            {"id": "d17a1af7-efa5-42ca-b7e9-6a35282d737f"}
+            {
+              "id": "d17a1af7-efa5-42ca-b7e9-6a35282d737f",
+              "alterId": 10
+            }
           ]
         }
       ]
diff --git a/testing/scenarios/data/test_1_server.json b/testing/scenarios/data/test_1_server.json
index 40aafabe..e4b2efd9 100644
--- a/testing/scenarios/data/test_1_server.json
+++ b/testing/scenarios/data/test_1_server.json
@@ -11,7 +11,8 @@
       "clients": [
         {
           "id": "d17a1af7-efa5-42ca-b7e9-6a35282d737f",
-          "level": 1
+          "level": 1,
+          "alterId": 10
         }
       ]
     }