How to unlock Phantom Prospect Assignment

There is a Phantom Prospect assignment from the China Rising expansion.  Before the unlock, the requirements for the assignment are a "?".  If you are premium using IE or Chrome, go to the Leaderboard on Battlelog and at the bottom left of the page is a skull.  Click on the skull and it will open a window and log you in and ask for a password.  The password is bumpinthenight.  This will unlock that assignment.

Some are theorizing you'll need this unlocked to release a Megladon on Paracel Storm.  They haven't figured out how yet, but from what it took to get the unlock, it could be part of something.