diff --git a/server.go b/server.go
index b3463aa..15047cf 100644
--- a/server.go
+++ b/server.go
@@ -120,8 +120,8 @@ func (s *server) handleRequest(ctx *fasthttp.RequestCtx) {
 		return
 	}
 	var responseHeader *fasthttp.ResponseHeader
-	var allowHandshake bool
-	if allowHandshake, responseHeader = socketHandler.Handshake(ctx); !allowHandshake {
+	var socketID interface{}
+	if socketID, responseHeader = socketHandler.Handshake(ctx); nil == socketID {
 		s.handleError(ctx, http.StatusNotAcceptable, fmt.Errorf("Server: Handshake err"))
 		return
 	}
@@ -132,7 +132,7 @@ func (s *server) handleRequest(ctx *fasthttp.RequestCtx) {
 			return
 		}
 
-		soc := newSocket(conn, socketHandler)
+		soc := newSocket(socketID, conn, socketHandler)
 
 		s.stopWg.Add(1)
 		handleConnection(s, soc, socketHandler)
diff --git a/socket.go b/socket.go
index f7b11d5..06ea3ca 100644
--- a/socket.go
+++ b/socket.go
@@ -9,10 +9,11 @@ import (
 	"git.loafle.net/commons_go/websocket_fasthttp/websocket"
 )
 
-func newSocket(conn *websocket.Conn, sh SocketHandler) *Socket {
+func newSocket(id interface{}, conn *websocket.Conn, sh SocketHandler) *Socket {
 	s := retainSocket()
 	s.Conn = conn
 	s.sh = sh
+	s.id = id
 	s.SetReadLimit(sh.GetMaxMessageSize())
 	if 0 < sh.GetReadTimeout() {
 		s.SetReadDeadline(time.Now().Add(sh.GetReadTimeout() * time.Second))
@@ -25,9 +26,30 @@ type Socket struct {
 	*websocket.Conn
 	sh SocketHandler
 
+	id         interface{}
+	attributes map[interface{}]interface{}
+
 	sc *SocketConn
 }
 
+func (s *Socket) ID() interface{} {
+	return s.id
+}
+
+func (s *Socket) GetAttribute(key interface{}) interface{} {
+	if nil == s.attributes {
+		return nil
+	}
+	return s.attributes[key]
+}
+
+func (s *Socket) SetAttribute(key interface{}, value interface{}) {
+	if nil == s.attributes {
+		s.attributes = make(map[interface{}]interface{})
+	}
+	s.attributes[key] = value
+}
+
 func (s *Socket) WaitRequest() (*SocketConn, error) {
 	if nil != s.sc {
 		releaseSocketConn(s.sc)
@@ -141,6 +163,7 @@ func retainSocket() *Socket {
 func releaseSocket(s *Socket) {
 	s.sh = nil
 	s.sc = nil
+	s.id = nil
 
 	socketPool.Put(s)
 }
diff --git a/socket_handler.go b/socket_handler.go
index aa485e7..46ebe57 100644
--- a/socket_handler.go
+++ b/socket_handler.go
@@ -7,7 +7,9 @@ import (
 )
 
 type SocketHandler interface {
-	Handshake(ctx *fasthttp.RequestCtx) (connectable bool, extensionsHeader *fasthttp.ResponseHeader)
+	// Handshake do handshake client and server
+	// id is identity of client socket. if id is nil, disallow connection
+	Handshake(ctx *fasthttp.RequestCtx) (id interface{}, extensionsHeader *fasthttp.ResponseHeader)
 	Handle(soc *Socket, stopChan <-chan struct{}, doneChan chan<- struct{})
 
 	GetMaxMessageSize() int64
diff --git a/socket_handlers.go b/socket_handlers.go
index 20aa04a..b8ce65b 100644
--- a/socket_handlers.go
+++ b/socket_handlers.go
@@ -27,8 +27,8 @@ type SocketHandlers struct {
 	PingPeriod  time.Duration
 }
 
-func (sh *SocketHandlers) Handshake(ctx *fasthttp.RequestCtx) (bool, *fasthttp.ResponseHeader) {
-	return true, nil
+func (sh *SocketHandlers) Handshake(ctx *fasthttp.RequestCtx) (id interface{}, extensionsHeader *fasthttp.ResponseHeader) {
+	return nil, nil
 }
 
 func (sh *SocketHandlers) Handle(soc *Socket, stopChan <-chan struct{}, doneChan chan<- struct{}) {