Fix a vulnerability in password encryption

* There was an error in the encryption used to save passwords,
  now it's really harder to decrypt the password from the config file
* Other minor changes

src/client/const.h

@@ -349,6 +349,7 @@ namespace Otc
         GameLoginPending = 35,
         GameNewSpeedLaw = 36,
         GameForceFirstAutoWalkStep = 37,
+        GameLoginUUID = 38,
         // 51-100 reserved to be defined in lua
         LastGameFeature = 101
     };

src/client/protocolgamesend.cpp

@@ -24,6 +24,8 @@
 #include "game.h"
 #include "client.h"
 #include <framework/core/application.h>
+#include <framework/platform/platform.h>
+#include <framework/util/crypt.h>
 
 void ProtocolGame::send(const OutputMessagePtr& outputMessage)
 {
@@ -97,6 +99,12 @@ void ProtocolGame::sendLoginPacket(uint challengeTimestamp, uint8 challengeRando
         paddingBytes -= 8 + m_characterName.length() + m_accountPassword.length();
     }
 
+    if(g_game.getFeature(Otc::GameLoginUUID)) {
+        std::string uuid = g_crypt.getMachineUUID();
+        msg->addString(uuid);
+        paddingBytes -= 2 + uuid.length();
+    }
+
     if(g_game.getFeature(Otc::GameChallengeOnLogin)) {
         msg->addU32(challengeTimestamp);
         msg->addU8(challengeRandom);