diff --git a/proxy/vmess/id.go b/proxy/vmess/id.go
index d40f5b7ef..afc51ff1e 100644
--- a/proxy/vmess/id.go
+++ b/proxy/vmess/id.go
@@ -33,18 +33,15 @@ func (this *ID) UUID() *uuid.UUID {
 	return this.uuid
 }
 
-func NewID(uuid *uuid.UUID) *ID {
-	md5hash := md5.New()
-	md5hash.Write(uuid.Bytes())
-	md5hash.Write([]byte("c48619fe-8f02-49e0-b9e9-edf763e17e21"))
-	cmdKey := md5.Sum(nil)
-
-	return &ID{
-		uuid:   uuid,
-		cmdKey: cmdKey,
-	}
-}
-
 func (v ID) CmdKey() []byte {
 	return v.cmdKey[:]
 }
+
+func NewID(uuid *uuid.UUID) *ID {
+	id := &ID{uuid: uuid}
+	md5hash := md5.New()
+	md5hash.Write(uuid.Bytes())
+	md5hash.Write([]byte("c48619fe-8f02-49e0-b9e9-edf763e17e21"))
+	md5.Sum(id.cmdKey[:0])
+	return id
+}