diff --git a/gold/link/crypto.go b/gold/link/crypto.go
index 070faf9..810a85c 100644
--- a/gold/link/crypto.go
+++ b/gold/link/crypto.go
@@ -7,6 +7,8 @@ import (
 	"errors"
 	"math/bits"
 	mrand "math/rand"
+
+	"github.com/sirupsen/logrus"
 )
 
 var (
@@ -51,7 +53,7 @@ func expandkeyunit(v1, v2 byte) (v uint16) {
 
 // Encode 使用 xchacha20poly1305 和密钥序列加密
 func (l *Link) Encode(teatype uint8, additional uint16, b []byte) (eb []byte) {
-	if b == nil || teatype >= 32 {
+	if len(b) == 0 || teatype >= 32 {
 		return
 	}
 	if l.keys[0] == nil {
@@ -61,6 +63,7 @@ func (l *Link) Encode(teatype uint8, additional uint16, b []byte) (eb []byte) {
 	}
 	aead := l.keys[teatype]
 	if aead == nil {
+		logrus.Warnln("[crypto] cipher key at index", teatype, "is empty")
 		return
 	}
 	eb = encode(aead, additional, b)
@@ -69,7 +72,7 @@ func (l *Link) Encode(teatype uint8, additional uint16, b []byte) (eb []byte) {
 
 // Decode 使用 xchacha20poly1305 和密钥序列解密
 func (l *Link) Decode(teatype uint8, additional uint16, b []byte) (db []byte, err error) {
-	if b == nil || teatype >= 32 {
+	if len(b) == 0 || teatype >= 32 {
 		return
 	}
 	if l.keys[0] == nil {
diff --git a/lower/nic.go b/lower/nic.go
index e6495a9..c9d416b 100644
--- a/lower/nic.go
+++ b/lower/nic.go
@@ -31,7 +31,8 @@ type NIC struct {
 func NewNIC(ip, subnet, mtu string, cidrs ...string) NICIO {
 	ifce, err := water.New(water.Config{DeviceType: water.TUN})
 	if err != nil {
-		panic(err)
+		logrus.Error(err)
+		os.Exit(1)
 	}
 	n := &NIC{
 		ifce:   ifce,
diff --git a/upper/services/wg/wg.go b/upper/services/wg/wg.go
index d9632a2..0feffbb 100644
--- a/upper/services/wg/wg.go
+++ b/upper/services/wg/wg.go
@@ -54,10 +54,8 @@ func (wg *WG) Start(srcport, destport uint16) {
 
 func (wg *WG) Run(srcport, destport uint16) {
 	wg.init(srcport, destport)
-	_, err := wg.me.ListenNIC()
-	if err != nil {
-		logrus.Warnln(err)
-	}
+	_, _ = wg.me.ListenNIC()
+	logrus.Info("[wg] stopped")
 }
 
 func (wg *WG) Stop() {