add encryption

libs/main/client_server/piclient_server_server.h

@@ -49,7 +49,7 @@ public:
 
 	void setClientFactory(std::function<Client *()> f) { client_factory = f; }
 
-	void write(Client * c, const PIByteArray & data);
+	void enableSymmetricEncryption(const PIByteArray & key);
 
 protected:
 	virtual void readed(Client * c, PIByteArray data) {}
@@ -61,6 +61,7 @@ private:
 	std::function<Client *()> client_factory;
 	PIEthernet * tcp_server = nullptr;
 	PIThread * clean_thread = nullptr;
+	PIByteArray crypt_key;
 	PIVector<Client *> clients;
 	PIMutex clients_mutex;