Note Cipher Puzzle

This page contains content from Underrail: Expedition expansion.

Note Cipher Puzzle
Unmarked quest (No notes)
Quest information
Location	Nexus of Technology
Given by	N/A
Rewards	Sonocaster unique pistol Lemurian Note Sheet 5 XP oddity Super Steel Refining Data high quality Super Steel Plates Naga Protector Diagnostic and Configuration Tool (Black Sea)

Optional puzzle that gives you access to Nexus Tech Vault containing Sonocaster pistol, Lemurian Note Sheet oddity, Super Steel Refining Data, high quality Super Steel Plates, Naga Protector Diagnostic and Configuration Tool (Black Sea) and some tech loot.

Objectives

N/A

Walkthrough

Like the Mutagen Puzzle, this is a major puzzle that usually requires out-of-game efforts to solve. It is a music-themed cryptography puzzle where you have to break a musical note cipher. You will get both the ciphertext and its decryption keys, so the objective of the puzzle is to read the instructions and implement a decipher.

The solution for this puzzle is different for each playthrough, but the same decipher will work for any given ciphertext and its keys. The puzzle also changes with difficulty.

• Easy: A separate encrypted line which contains the tech vault keycode digits, alongside random titles of lemurian compositions that can be used to test your solution before decrypting the numerical code.
• Normal: The encrypted keycode line is removed. Instead, it is randomly inserted into the lemurian compositions. Keycode digits may appear as text (e.g. six instead of 6).
• Hard: Punctuation, spaces and the like are ditched. Instead, all symbols are in groups of five. Roughly 7% of characters are corrupted, appearing as an asterisk.
• DOMINATING: Same as hard. Corruption frequency might be higher.^Verify

Puzzle hint locations

• Nexus of Technology, administration and IT floor, Mickey Johnson's computer
  • Theory:Bits_and_Pieces_for_Unschooled_People.odc: Explanation of the puzzle's music theory theme
  • New challenge Mail: Mickey's ciphertext

• Nexus of Technology, security technology floor, Allan McLane's computer
  • Musical_Cipher_Keys.odc: Mickey's cipherkeys

Note: Use Ctrl + C to copy current dialog to clipboard. Allows easily exporting Mickey's ciphertext and keys from the game in plain text format.

Random puzzle text

These are the random titles of Lemurian compositions used in the puzzle, before any added corruption or tech vault keypad digits. If your own deciphering solution is not forming any sensible text, these might help pinpoint the error without relying on solvers written by others.

Lemurian composition titles

Hydrothermal Genesis Ode to the Sun Of Annihilated Past and Future Abyssal Horrors Servant Dance Lemuria - A Hymn to New Beginnings Mail from a World Gone by Cultivating Light in Darkness Claustrophilic Destiny Polychromatic Waterscapes Dreams of Asphyxiation Crimson Meadow Ballet The Towering Stars The Rite of Spring Tide Prismatic Soot March of the Protectors Linda the Handmaiden Strongman Etude Electrolin Concerto Marriage of a Subislander Genetic Intervention Omnipresent Pressure Celestial Nostalgia Restless Waves Caprice Citadel of Death Coral Fantasy The Barber of Subisle Rime of the Security Marine The Rhythm of Extinction

Solution

The cipher in this puzzle is essentially a substitution cipher. The symbols in the original text are substituted with different symbols (musical notes in this case) using a table, said table being the key to the cipher. Having this key and an encrypted text (ciphertext) on hand, we can perform inverse substitution to recieve the original text. The actual puzzle in this case is in figuring out what is the ciphertext and what is the key while the instructions are not well worded and kind of backwards.

Example (DOMINATING difficulty)

Mickey's text:
A#D#AC#BF BCDB FC#D#
AD#A#BA#D# A#A#A#D BC#D#A#C# BGAGC#D#
GbEFGGA D#A#D#FB EGAD#A# A#CAD#
C#GbABA# DEBFB BA#G

Mickey's interval key: major seventh, perfect fourth, minor sixth.

Mickey's octave keys:
Key 1: 3607478377243744
Key ?: 360747744771838474377444
Key ?: 36077747747477277477874
Key ?: 3604773424377371

First let's build the key. The rows in this substitution table represent octaves while the columns are notes in them.

	C	C# / Db	D	D# / Eb	E	F	F# / Gb	G	G# / Ab	A	A# / Bb	B
0
1
2
3
4
5
6
7
8
9

Step 1

The first three numbers in every octave key are the octave numbers (rows in our table) where the symbols of the alphabet are originally placed.
In this case, they are 3, 6, 0. Fill the octaves in order: A-L in row 3; M-X in row 6; Y-Z and 0-9 in row 0:

	C	C#	D	D#	E	F	F#	G	G#	A	A#	B
0	Y	Z	0	1	2	3	4	5	6	7	8	9
1
2
3	A	B	C	D	E	F	G	H	I	J	K	L
4
5
6	M	N	O	P	Q	R	S	T	U	V	W	X
7
8
9

Step 2

Next, every one of these three rows needs to be offset by a certain number we get from the Mickey's interval key.
Translate the intervals to numbers using the table found on Mickey's computer.
major seventh = 11
perfect fourth = 5
minor sixth = 8

Step 3

Move the letters in the cells to the right according to these numbers.
A-L needs to be offset by 11 positions

	C	C#	D	D#	E	F	F#	G	G#	A	A#	B
3												A
4	B	C	D	E	F	G	H	I	J	K	L

M-N needs to be offset by 11 + 5 = 16 which means an entire row (octave) and then another 16 - 12 = 4 positions

	C	C#	D	D#	E	F	F#	G	G#	A	A#	B
6
7					M	N	O	P	Q	R	S	T
8	U	V	W	X

Y-9 needs to be offset by 11 + 8 = 19, once again more than an entire row

	C	C#	D	D#	E	F	F#	G	G#	A	A#	B
0
1								Y	Z	0	1	2
2	3	4	5	6	7	8	9

This gives us our key. I omitted any empty rows as they don't matter.

	C	C#	D	D#	E	F	F#	G	G#	A	A#	B
1								Y	Z	0	1	2
2	3	4	5	6	7	8	9
3												A
4	B	C	D	E	F	G	H	I	J	K	L
7					M	N	O	P	Q	R	S	T
8	U	V	W	X

Step 4

The puzzle is half done now. Let's figure out what the actual ciphertext is. It is split in two parts; the notes (columns) are in the text on the Mickey's computer, the octaves (rows) are in his octave keys down on the Allan's computer.
Each of the octave keys (minus the first three of its numbers we used in step 1) corresponds to a line in Mickey's text.
Take the first line and add the octave numbers from the first octave key to the notes. I removed the spaces as they are randomly placed, at least on DOMINATING.

A#	D#	A	C#	B	F	B	C	D	B	F	C#	D#
7	4	7	8	3	7	7	2	4	3	7	4	4

Step 5

Perform the inverse substitution to read the original text
The numbers are the octaves (rows) in our key table while the notes are the columns. Thus A# in the 7th octave translates to S, D# in the 4th octave translates to E etc.
The first line is therefore: servant3dance. That 3 sticks out as the first digit of our code.

Repeating steps 4 and 5 for the remaining lines, we get:
servant3dance
restless1wavescaprice
omnipresent7pressure
coral5fantasy

And the code, 3175. Yours might turn out less easily readable.

External links

Guides

• https://steamcommunity.com/sharedfiles/filedetails/?id=1814351290 — The Utter Pipeworker's Guide to the Musical Cipher

Solving tools

• https://underrail.com/forums/index.php?topic=4197.0 — Underrail Expedition Music Decipher by hilfazer (offline executable)
• https://shibatora.github.io/underrailmusicpuzzlesolver/ — Underrail Expedition Music Puzzle Solver (hosted online, source code)
• https://poligon.hekko24.pl/underrail/ — Underrail Expedition music puzzle help tool by @MZ (hosted online)