diff --git a/src/main/res/values-ru/strings.xml b/src/main/res/values-ru/strings.xml
index 06ae9864..98a5222a 100644
--- a/src/main/res/values-ru/strings.xml
+++ b/src/main/res/values-ru/strings.xml
@@ -60,6 +60,7 @@
   <string name="forward_success">Shadowsocks запущен.</string>
   <string name="invalid_server">Неправильное имя сервера</string>
   <string name="service_failed">Ошибка при подключении к удалённому серверу</string>
+  <string name="method_unsafe">ВНИМАНИЕ:В настоящее время метод шифрования является небезопасным</string>
   <string name="nat_deprecated">ВНИМАНИЕ:режим NAT не работает в Android 5.0</string>
   <string name="nat_no_root">Режим NAT требует наличия ROOT прав</string>
   <string name="switch_to_vpn">Переключить на режим VPN</string>
diff --git a/src/main/res/values-zh-rCN/strings.xml b/src/main/res/values-zh-rCN/strings.xml
index f91ce369..6309eb9a 100644
--- a/src/main/res/values-zh-rCN/strings.xml
+++ b/src/main/res/values-zh-rCN/strings.xml
@@ -35,6 +35,7 @@
   <string name="forward_success">后台服务已开始运行。</string>
   <string name="service_failed">无法连接远程服务器</string>
   <string name="invalid_server">服务器名无效</string>
+  <string name="method_unsafe">警告：当前使用的加密算法不安全</string>
   <string name="nat_deprecated">警告：在 Android 5.0 及更高版本中不建议使用 NAT 模式</string>
   <string name="nat_no_root">NAT 模式需要 ROOT 权限</string>
   <string name="switch_to_vpn">切换到 VPN 模式</string>
diff --git a/src/main/res/values-zh/strings.xml b/src/main/res/values-zh/strings.xml
index d455536e..94af6526 100644
--- a/src/main/res/values-zh/strings.xml
+++ b/src/main/res/values-zh/strings.xml
@@ -36,6 +36,7 @@
   <string name="forward_success">Shadowsocks 已啟動。</string>
   <string name="service_failed">連線至遠端伺服器失敗</string>
   <string name="invalid_server">伺服器名稱無效</string>
+  <string name="method_unsafe">警告：當前使用的加密算法不安全</string>
   <string name="nat_deprecated">警告：自 Android 5.0 開始， NAT 模式已過時</string>
   <string name="nat_no_root">NAT 模式需要 ROOT 權限</string>
   <string name="switch_to_vpn">切換至 VPN 模式</string>
diff --git a/src/main/res/values/strings.xml b/src/main/res/values/strings.xml
index 078c0d24..8c472f3b 100644
--- a/src/main/res/values/strings.xml
+++ b/src/main/res/values/strings.xml
@@ -66,6 +66,7 @@
   <string name="forward_success">Shadowsocks started.</string>
   <string name="invalid_server">Invalid server name</string>
   <string name="service_failed">Failed to connect the remote server</string>
+  <string name="method_unsafe">WARNING: The current encryption method is unsafe</string>
   <string name="nat_deprecated">WARNING: NAT mode has been deprecated since Android 5.0</string>
   <string name="nat_no_root">NAT mode requires ROOT permission</string>
   <string name="switch_to_vpn">Switch to VPN mode</string>
diff --git a/src/main/scala/com/github/shadowsocks/BaseService.scala b/src/main/scala/com/github/shadowsocks/BaseService.scala
index d2cea36d..c65143b1 100644
--- a/src/main/scala/com/github/shadowsocks/BaseService.scala
+++ b/src/main/scala/com/github/shadowsocks/BaseService.scala
@@ -166,6 +166,8 @@ trait BaseService extends Service {
 
     changeState(State.CONNECTING)
 
+    if (profile.isMethodUnsafe) Toast.makeText(this, R.string.method_unsafe, Toast.LENGTH_LONG).show
+
     Utils.ThrowableFuture(connect)
   }
 
diff --git a/src/main/scala/com/github/shadowsocks/database/Profile.scala b/src/main/scala/com/github/shadowsocks/database/Profile.scala
index ede0c720..19570fd3 100644
--- a/src/main/scala/com/github/shadowsocks/database/Profile.scala
+++ b/src/main/scala/com/github/shadowsocks/database/Profile.scala
@@ -101,4 +101,6 @@ class Profile {
 
   override def toString = "ss://" + Base64.encodeToString("%s%s:%s@%s:%d".formatLocal(Locale.ENGLISH,
     method, if (auth) "-auth" else "", password, host, remotePort).getBytes, Base64.NO_PADDING | Base64.NO_WRAP)
+
+  def isMethodUnsafe = "table".equalsIgnoreCase(method) || "rc4".equalsIgnoreCase(method)
 }