I usually like to go to YouTube.com and follow JackFrags for these questions. He usually has a really easy step-by-step on how to unlock the videos.
I found this one for you:
Based off of several special pictographs that were found in Dragon's Teeth map pack (eight of which), They placed these in a 64 hexagram table that gives each picture a set of numbers. These numbers correspond with the Fibonacci sequence. Changing them from numbers to tri-pictographs then to unicode decimals, you get a sent of numbers (lots of numbers I won't get into). Getting those numbers, you have to changed them from Largest to smallest.
So you get these long Unicode Decimals, DICE dropped a hit stating that "X marks the spot. The Greek one". Well inside the Battlelog Password screen, the Greek X (CHI) was given a number (7.something).
Well, you Multiple the Unicode Decimal (which we'll call U) and multiple CHI^i++:
Ux^0 + Ux^1 + ... U*x^7
Which equals 24344241893.stuff
In the Password screen, they have a parameter called (max, floor). We used max earlier to change the numbers to start largest to smallest. Now we use the floor method to drop all the numbers after the decimal point.
So, Long story short, the answer is 24344241893. Enter that into Battlelog and you'll unlock the next phantom mission.
Also, from Battlelog itself, a forum dedicated to getting Phase 4.
Granted this is from November 11th. But this should still apply.
How to access the Phantom Terminal
1)Make sure you have premium on your account
2)Go to the LEADERBOARDS page
3)Scroll to the bottom of the page
4)Click the little skull icon to show the Phantom Terminal
Previous Phantom Program Passwords
Phase 1: bumpinthenight
Phase 2: epic dream worlds
Phase 3: 24344241893
In what may turn out to be one of the most intricate Easter eggs in video game history, it appears that after nearly a year of clues, the developers at DICE are ready to wrap up the Phantom Program in Battlefield 4.
As has been the case for the last few DLC releases, Final Stand has players across the Battlefield universe trying to crack the code to the Phantom Program, this time focusing on the Phantom Operative.
How can I complete the Phantom Operative assignment and unlock the Phantom Bow?
It's currently not known how the Phantom Operative assignment can be unlocked on Battlelog, but there are some clues that elude to how the mystery will eventually unravel.
When players go to Battlelog, then click on the Leaderboards option at the top, they can scroll to the bottom of the page and find a tiny skull icon on the left side. Clicking on this icon will bring up several lines of fake code that are as follows.
dracut: Scanning devices sda2 for LVM logical volumes sysvg/root sysvg/swap
dracut: inactive '/dev/sysvg/root' [28.88 GiB] inherit
dracut: inactive '/dev/sysvg/swap' [1.00 GiB] inherit
>>> INITIALIZING PHANTOM PROGRAM <<<
Current user: x-Rumpo-x
PREMIUM USER identified
dracut: rd_NO_MD: removing MD RAID activation
ata_piix 0000:00:01.1: version 2.13
ata_piix 0000:00:01.1: setting latency timer to 64
scsi0 : ata_piix
scsi1 : ata_piix
ata1: PATA max MWDMA2 cmd 0x1f0 ctl 0x3f6 bmdma 0xc000 irq 14
ata2: PATA max MWDMA2 cmd 0x170 ctl 0x376 bmdma 0xc008 irq 15
ata1.01: NODEV after polling detection
ata1.00: ATA-7: QEMU HARDDISK, 0.12.1, max UDMA/100
ata1.00: 62914560 sectors, multi 16: LBA48
ata1.00: configured for MWDMA2
scsi 0:0:0:0: Direct-Access ATA QEMU HARDDISK 0.12 PQ: 0 ANSI: 5
virtio-pci 0000:00:04.0: PCI INT A -> Link[LNKD] -> GSI 11 (level, high) -> IRQ 11
>> Assignment 3 unlocked
Phase 4 now active. Physical access restriction in place.
Here is where it gets interesting. The final line tells us that there is a physical access restriction in place, and it just so happens a few players have found the Phantom Room, located at the A Flag on Hanger 21. The room is reached via elevator, and when players arrive they must enter a code to remove a physical barrier that blocks access to the room. The code is not currently known.
According to the Battlefield 4 Reddit, the code has been found and proven to work. Once you manage to survive the elevator ride (instructions below), input 1290 429 397648 970 into the keypad. This will grant you access to the room where the Phantom Bow can be found.
How do I use and survive the elevator?
If you've watched any of the videos that JackFrags has released over the last several days, you'll know that it's very easy to die in this elevator. The key to survival, it would seem, is to make sure you have all three of the previous Phantom assignments complete.
It also appears that you need four people in your squad, each having completed all three of the above linked assignments. Each player must also have one of the Phantom dog tags equipped as their right dog tag, as well as one of the unique ones that can currently be found on Final Stand maps. We've even seen players wearing Phantom camouflage on their soldier, as well as their weapons. We can't confirm all of this is necessary, but it also doesn't appear to hurt.
Where can I find the Final Stand dog tags? [Updated 11/23/2014]
These can be found on the four new maps that shipped with Final Stand. They are Hanger 21, Operation Whiteout, Hammerhead, and Giants of Karelia.
So far this is no definitive map that shows the location of all the dog tags and where they can be found, but community members over on the Battlefield Reddit are hard at work compiling one. For your best chance to find numerous dog tags, head on over and read through the thread they have posted. In fact, they have a detailed, up to date post with all the updated information.
I've reached the Phantom Room. Now what?
Now you're all caught up, since the code to continue on has yet to be discovered. When it is, and you've successfully entered it, be sure to check Battlelog to see if the Phantom Operative assignment has been unlocked.
Keep checking back to this post, as we'll continue to update it as we uncover new information. For now, check out the videos below to get a taste of what the Phantom Operative and Phantom Bow might have to offer.