Cryptographers use ciphers to encode messages so that they are essentially gibberish unless you know the key to decode the cipher. I decided to see how Stable Diffusion 2.1 responded to encoded prompts. To ensure that only the prompt was changing, I used the same seed for every cipher: 32823021. In the caption for each image I will tell you what cipher was used, as well as any additional information or settings that were used for the encoding. The original prompt is simply "Cthulhu", which will be the first image I give you.
Cthulhu
Caesar Cipher, Shift = 0
Bsgtkgt
Caesar Cipher, Shift = 1
Arfsjfs
Caesar Cipher, Shift = 2
Zqerier
Caesar Cipher, Shift = 3
Ypdqhdq
Caesar Cipher, Shift = 4
Xocpgcp
Caesar Cipher, Shift = 5
Wnbofbo
Caesar Cipher, Shift = 6
Vmanean
Caesar Cipher, Shift = 7
Ulzmdzm
Caesar Cipher, Shift = 8
Tkylcyl
Caesar Cipher, Shift = 9
Sjxkbxk
Caesar Cipher, Shift = 10
Riwjawj
Caesar Cipher, Shift = 11
Qhvizvi
Caesar Cipher, Shift = 12
Pguhyuh
Caesar Cipher, Shift = 13
Oftgxtg
Caesar Cipher, Shift = 14
Nesfwsf
Caesar Cipher, Shift = 15
Mdrevre
Caesar Cipher, Shift = 16
Lcqduqd
Caesar Cipher, Shift = 17
Kbpctpc
Caesar Cipher, Shift = 18
Jaobsob
Caesar Cipher, Shift = 19
Iznarna
Caesar Cipher, Shift = 20
Hymzqmz
Caesar Cipher, Shift = 21
Gxlyply
Caesar Cipher, Shift = 22
Fwkxokx
Caesar Cipher, Shift = 23
Evjwnjw
Caesar Cipher, Shift = 24
Duivmiv
Caesar Cipher, Shift = 25
Emoowoo
Vigenère Cipher, Key = Cthulhu
Soeawmi
Beaufort Cipher, Key = Uhluhtc
Thulhuc
Rozier Cipher, Key = Cthulhu
Azpcbpc
Affine Cipher, A Coefficient = 3, B Coefficient = 20
Wzfirboj
Hill Cipher, 2×2 Matrix = 3, 20/8, 21
Rebaasfo
Slidefair Cipher, Key = Cthulhu
Ocretre
Porta Cipher, Key = Cthulhu
Elsowwl
Jefferson Cipher
Iunbrdg
Phillips Cipher, Key = abcdefghijklmnopqrstuvwxyz
Gvghrif
Delastelle's Trifid Cipher, Grids = abcdefghi, jklmnopqr, stuvwxyz_
Djmwbjk
Delastelle's Bifid Cipher, Grid = abcdefghijklmnopqrstuvwxy
Erfwmgvy
PlayFair Cipher, Grid = abcdefghijklmnopqrstuvwxy
Apfwyuwukfuvwuu
Collon Cipher, Grid = abcdefghijklmnopqrstuvwxy
Fdfdfadgxggddd
ADFGVX Cipher, Grid = abcdefghijklmnopqrstuvwxyz1234567890
Tqqgywr
Enigma Machine (Wehrmacht/Luftwaffe 3 Rotors)
Final Thoughts: Stable Diffusion was unable to understand any of the coded messages. (Not that I thought it would.) But there were some themes that consistently emerged: dogs, birds, leaves, the desert, and the color orange. I suspect that these had something to do with the seed and/or the images that Stable Diffusion 2.1 was trained on; I doubt that there was a pattern that emerged across encryptions that Stable Diffusion was able to detect.
