What i've found in the code is what you need to do and what you get when you've unlocked it:
t['WARSAW_ID_P_XP3_AWARD_GHOST']="PHANTOM INITIATE";
t['WARSAW_ID_P_XP3_AWARD_GHOST_CRIT1']="
Get 200 LMG kills
";
t['WARSAW_ID_P_XP3_AWARD_GHOST_CRIT2']="
Get 50 kills with explosives
";
t['WARSAW_ID_P_XP3_AWARD_GHOST_CRIT3']="
Get 25 roadkills
";
t['WARSAW_ID_P_XP3_AWARD_GHOST_DESC']="
Unlocks Phantom weapon and vehicle camo
";
Still have no starting point for guessing the password. Maybe we must wait for the dragon's teeth maps to get a entry point for the research.
Edit: There is already a battlelog thread for that, they also found it in the code few hours ago.