Encodes text by replacing each letter with a different letter according to a fixed pattern.
Example
| Cipher Letter | A | B | C | D | E | F | G | … |
|---|---|---|---|---|---|---|---|---|
| Original Letter | D | H | E | J | O | L | M | … |
Encoded message BCFFE then decodes to HELLO
In an Aristocrat cipher, word spacing and punctuation are preserved to make solving easier.
A Patristocrat cipher removes these hints by running all letters together without spaces.
With random substitution, any letter can map to another arbitrary letter, there is no pattern
K1 and K2: there is a keyword and a location of the keyword. Letters outside of the keyword follow alphabetical order.
K1 example:
CAKE, location is 2| Cipher Letter | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | … |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Original Letter | Y | Z | C | A | K | E | B | D | F | G | H | I | J | L | M | N | O | … |
In the original letters row, the keyword CAKE starts at location 2 and is followed by the rest of the letters in A-Z order.
HELLO encodes to KFNNQ
K2 example:
CAT, location is 3| Cipher Letter | X | Y | Z | C | A | T | B | D | E | F | G | H | I | J | K | … |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Original Letter | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | … |
In the cipher letter row, the keyword CAT starts at location 3 and is followed by the rest of the letters in A-Z order.
Hello encodes to DHHAK
In all cases, each cipher letter cannot be the same as the original letter.
<aside> 💡
As a code breaker, you don’t know the keyword and the location of the keyword. You only know the encoded text, and your task is to find out the original message.
</aside>
Next, learn some Strategies