Coding & Decoding Guides
Translating messages using coding rules and substitution patterns
Letter-to-Number Codes
Each letter is replaced by its position in the alphabet.
View Guides →Number-to-Letter Codes
Decode numbers by converting each to its corresponding letter.
View Guides →Atbash Cipher
Each letter is replaced by its mirror in the alphabet (A to Z, B to Y, etc.).
View Guides →Caesar Cipher
Each letter is shifted by a fixed number of positions in the alphabet.
View Guides →Symbol Substitution
Letters are replaced with symbols according to a given key.
View Guides →Combined Codes
Multiple coding rules are applied in sequence.
View Guides →Polybius Square
Letters are encoded as coordinate pairs from a 5x5 grid.
View Guides →Variable Shift Cipher
Each letter shifts by its position number (1st +1, 2nd +2, etc.).
View Guides →Vowel-Consonant Code
Vowels and consonants follow different shift rules.
View Guides →Keyboard Cipher
Letters shift along their QWERTY keyboard row.
View Guides →Reverse Word
The word is spelled backwards (transposition, not substitution).
View Guides →Skip Cipher
Letters are rearranged by taking alternating positions.
View Guides →Binary Encoding
Represent each letter's alphabet position as a base-2 number (0s and 1s).
View Guides →Phone Keypad (Multi-tap) Encoding
Encode letters as (key, tap) pairs using the ITU E.161 phone keypad layout.
View Guides →Rail Fence Cipher
A transposition cipher that writes the plaintext in a zigzag across N rails and reads ciphertext row by row.
View Guides →ROT13 Cipher
A Caesar cipher with fixed shift of 13 that is its own inverse for the 26-letter Latin alphabet.
View Guides →Vigenère Cipher
A polyalphabetic substitution cipher using a repeating keyword to determine each letter's shift.
View Guides →