diff --git a/server/gameserver/GCListener.cc b/server/gameserver/GCListener.cc
index 08a5664..35ed4cd 100644
--- a/server/gameserver/GCListener.cc
+++ b/server/gameserver/GCListener.cc
@@ -11,10 +11,58 @@
 #include "jsondatamgr.h"
 #include "handlermgr.h"
 
+const static size_t CRYPTED_SEND_LEN = 4;
+const static size_t CRYPTED_RECV_LEN = 6;
+
 class GGClientSession: public a8::MixedSession
 {
 public:
 
+    virtual void Reset() override
+    {
+        a8::MixedSession::Reset();
+        send_i_ = 0;
+        send_j_ = 0;
+        recv_i_ = 0;
+        recv_j_ = 0;
+        initialized_ = false;
+    }
+
+    void DecryptRecv(unsigned char* data, size_t len)
+    {
+        if (!initialized_) {
+            return;
+        }
+        if (len < CRYPTED_RECV_LEN) {
+            return;
+        }
+        for (size_t t = 0; t < CRYPTED_RECV_LEN; t++) {
+            recv_i_ %= key_.size();
+            unsigned char x = (data[t] - recv_j_) ^ key_[recv_i_];
+            ++recv_i_;
+            recv_j_ = data[t];
+            data[t] = x;
+        }
+    }
+
+    void EncryptSend(unsigned char* data, size_t len)
+    {
+        if (!initialized_) {
+            return;
+        }
+
+        if (len < CRYPTED_SEND_LEN) {
+            return;
+        }
+
+        for (size_t t = 0; t < CRYPTED_SEND_LEN; t++) {
+            send_i_ %= key_.size();
+            unsigned char x = (data[t] ^ key_[send_i_]) + send_j_;
+            ++send_i_;
+            data[t] = send_j_ = x;
+        }
+    }
+
     virtual void DecodeUserPacket(char* buf, int& offset, unsigned int buflen) override
     {
         #if 1
@@ -67,6 +115,13 @@ public:
                                   .SetParam1(1));
     }
 
+private:
+    std::vector<unsigned char> key_;
+    unsigned char send_i_ = 0;
+    unsigned char send_j_ = 0;
+    unsigned char recv_i_ = 0;
+    unsigned char recv_j_ = 0;
+    bool initialized_ = false;
 };
 
 static void CreateGameClientSocket(a8::TcpSession **p)