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Encode, decode, and brute-force the Caesar cipher with any shift (1–25), or print all 25 candidate decodings.
Details
The Caesar cipher shifts each letter by a fixed number of places through the alphabet — history's most famous substitution cipher, supposedly used by Julius Caesar with a shift of 3.
Three modes:
A→D, H→K, Z→C. Non-letters (spaces, digits, punctuation) are left alone.Good to know:
Z + 1 → A).Execution
Fill in the form, run the tool, and review the result in one place.
Samples
Related
Tool usage guide
The Caesar Cipher tool allows you to easily encode, decode, and brute-force messages using the classic substitution cipher. By shifting letters by a fixed number of places from 1 to 25 or testing all 25 possible shifts simultaneously, you can quickly encrypt plain text, decrypt ciphertext, or solve ciphers without knowing the original shift key.
Background
A puzzle designer wants to hide a clue in a game using a shift of 5 so players have to decode it.
Problem
Encrypting the text while keeping the original capitalization and spacing intact.
How to use
Enter 'Meet at midnight' in the text field, set the mode to 'Encode', set the shift to 5, and ensure 'Preserve case' is checked.
Mode: Encode, Shift: 5, Preserve Case: TrueOutcome
The tool outputs the ciphertext 'Rjqy fy rninsnmy'.
Background
A student finds a ciphertext but does not know the shift key used to encrypt it.
Problem
Finding the correct shift value and reading the original message without manual trial and error.
How to use
Paste 'Khoor, Zruog!' into the text field, select 'Brute force' mode, and run the tool.
It is a substitution cipher where each letter in the plaintext is shifted a fixed number of places down the alphabet.
Yes, ROT13 is simply a Caesar cipher with a shift of 13, which you can run by setting the shift value to 13.
It generates and displays all 25 possible shift combinations, allowing you to easily identify the readable English output.
No, the tool only shifts alphabetic characters; numbers, spaces, and punctuation remain unchanged.
No, it is highly insecure and easily broken; it should only be used for puzzles, education, and historical interest.
Mode: Brute force, Preserve Case: TrueOutcome
The tool outputs all 25 possible decodings, showing 'Hello, World!' at shift 3.