I've been working on the final Marquee cipher for some time now with computer assistance, and have seemingly made some progress. It is deterministic up to a point but some steps are more backed by strong evidence rather than being deterministic. I am not claiming I have solved it, but I would like to see what you guys think.
Here is my strongest result:
The cipher text can be split at its unique parentheses into:
- a 39-character main section which divides into 13 groups of 3.
- a 27-character instruction section.
Said instruction section contains +9-7 and using those numbers to walk through the 32 ASCII characters from ! to @, and lining the walk up with a padded old-style phone keypad alphabet seemingly produces a full substitution system.
One small encouraging sign is part of the instruction section "2enr?" turns to "HENRY".
The remaining characters can be arranged into a small 2-by-2 mathematical operation. Importantly, the packet includes a self answer check, as it predicts "YG" and the calculation also produces "YG".
Applying this operation to the 13 groups from the marquee produce the pairs:
"fo lr zt as es ek uq 5h pl op i6 3r ji"
The two adjacent 3s in the original cipher act as the final combining instruction; combining each pair gives:
"PASSTOLPCFUUR"
or
"PASS TO LPCFUUR"
To me, this seems quite strong as I tested thousands of alternatives with computer assistance. From 4,096 reasonable phone layout and alignment variations, only this version created "HENRY", passed the built in "YG" check and began with "PASS TO".
Testing all 1,024 possible 2-character combining choices and this was the only one producing an answer beginning with PASS.
Reading the rest:
What follows is more interpretive than mathematically forced. Let me know what you think.
The marquee supplies the alternating shifts +9, -7, so we apply those shifts to the remaining 7 letters, which gives:
L P C F U U R
+9 -7 +9 -7 +9 -7 +9
U I L Y D N A
The exact result is "UILY DNA"
On a telephone keypad, both UILY and UGLY have the same digits of 8459, so in my opinion, the most natural T9 interpretation is "PASS TO UGLY DNA".
"PASS TO UGLY DNA" instruction:
What follows is how the phrase "PASS TO UGLY DNA" may function as an instruction.
Before the two adjacent 3's combine each result to one character, the calculation produces these 13 ordered pairs (from earlier):
"fo lr zt as es ek uq 5h pl op i6 3r ji"
This means there are 13 paired positions, or 26 symbols still available for a possible second stage. The train cars on the map contain exactly 13 opposing left/right panel pairs and gives 26 individual positions. This could indicate a link from the marquee to the map environment:
13 cipher pairs <-> 13 train-panel pairs
1st character <-> left panel
2nd character <-> right panel
Under this interpretation, the phrase "PASS TO UGLY DNA" could be read as the following instructions:
PASS TO --> pass uncombined pairs into another stage
DNA --> arrange them as 2 corresponding left/right "strands"
UGLY --> look at the visually abnormal members of those strands
Back in 2016, a transcription marked 4 panels as unusually bright. Using the order of the panels and selecting the character on the corresponding bright side gives:
| Position |
Cipher Pair |
Bright Side |
Selected Character |
| 2 |
lr |
right |
r |
| 4 |
as |
left |
a |
| 7 |
uq |
right |
q |
| 11 |
i6 |
left |
i |
This produces "RAQI". The brightness determines which character to select, while the selected panel's colour determine how the character is shifted.
The map associates the relevant route colours with these numbers:
blue = 14
red = 271
green = 48
Using these as forward alphabet shifts, reduced modulo 26, gives:
R + blue 14 = F
A + red 271 = L
Q + blue 14 = E
I + green 48 = E
Therefore "RAQI" --> "FLEE"
Conclusion:
I am fairly confident the "PASS TO" section is intended, but not 100% certain. The train-panel route to "FLEE" seems to be a coherent continuation but would still need verification i.e. confirming the same 4 panels are consistently brighter at positions 2R, 4L, 7R and 11L.
It was also said in 2017 that the code was on (and limited to) the scrolling marquee sign, so potentially the in-game continuation may not be true.
p.s. obviously this is just an overview and the math and substitution systems are more detailed, so I will explain those if this is deemed intended. If I haven't explained something clearly, please ask any questions.
references:
https://www.reddit.com/r/DestinyTheGame/comments/575mq4/apparently_theres_a_code_in_last_ex
https://www.reddit.com/r/raidsecrets/comments/575o4v/last_exit_hidden_codesecret/
https://destiny.bungie.org/forum/index.php?id=146937&mode=thread
https://www.ishtar-collective.net/cards/last-exit-ishtar-sink-venus