The latest Battlefield 4 DLC, Naval Strike, has another secret assignment called "Phantom Trainee". Finding out how to unlock it involved a fake player, morse code, the viking alphabet and a bunch of other crazy secrets.
YouTuber JackFrags walks us through the process of how the secrets were unlocked in he video above. You have to open up the console using the phantom program icon on the bottom left corner of the battlelog leaderboard and use the password "bumpinthenight" to unlock the Phantom Program. Then the next password is "epic dream worlds" (with spaces). Then you're just a few hundred kills away from a fancy new camo unlock!
Phantom Trainee Password [JackFrags]