Ciphers
Simple substitution
Also found as general simple substitution · monoalphabetic substitution · cryptogram
How it works
Write a 26-letter cipher alphabet under A–Z. Each plaintext letter becomes the letter below it; decryption looks up the mapping in reverse. The complete cipher alphabet is the Key Decipher uses. A keyword can help build it, but two keywords that produce the same alphabet produce the same cipher.Military Cryptanalytics, Part I
Cᵢ = π(Pᵢ)Pᵢ = π⁻¹(Cᵢ)Worked example
- Plain
ABCDEFGHIJKLMNOPQRSTUVWXYZ- Cipher
QWERTYUIOPASDFGHJKLZXCVBNM- Plaintext
MEET- Ciphertext
DTTZ
What to look for
The symbols change, but their positions do not. You can still compare letter frequencies, word shapes and repeated positions, doubled letters, apostrophes, and repeated words. A possible mapping must agree with every occurrence of the same symbol; keep competing claims separate in a hypothesis.Military Cryptanalytics, Part IGaines, Cryptanalysis
Aristocrat and Patristocrat
In Decipher, Aristocrat and Patristocrat are Challenge Formats built on general simple substitution. Aristocrat keeps spaces and punctuation. Patristocrat removes them and displays the letters in groups of five. Both formats also rule out letters that encrypt to themselves.ACA AristocratACA Patristocrat