UtilityBaseText Tools
Cipher Encoder & Decoder
Encode and decode Caesar, ROT13, Atbash, and Vigenère ciphers, with brute-force Caesar cracking.
Updated July 10, 2026
How to use the cipher encoder & decoder
- 1Choose a cipher.
- 2Set the shift or keyword if needed.
- 3Type your text and pick encode or decode.
- 4For an unknown Caesar, read the brute-force list.
Common uses
- Solving a cipher puzzle or escape room
- Decoding a Caesar or Vigenère message
- CTF and cryptography practice
- Learning how classic ciphers work
Frequently asked questions
How do I crack a Caesar cipher without the shift?
Use the brute-force view, which lists all 25 possible shifts of your text at once. Scan the list for the line that reads as normal words — that's the decoded message and its shift.
Is ROT13 the same as Caesar?
Yes, ROT13 is a Caesar cipher with a shift of 13. Because the alphabet has 26 letters, applying ROT13 twice returns the original text, so the same operation both encodes and decodes.
Are these ciphers secure?
No. Caesar, ROT13, Atbash, and even Vigenère are easily broken and are meant for puzzles and learning, not protecting real secrets. Use modern encryption for anything sensitive.
About this tool
This cipher tool encodes and decodes text with the classic substitution ciphers: Caesar (a fixed letter shift), ROT13, Atbash (the reversed alphabet), and Vigenère (a keyword-based shift). For a Caesar cipher whose shift you don't know, it shows all 25 possible decodings so you can spot the readable one. It's made for puzzles, escape rooms, CTF challenges, and learning how ciphers work — not for real security. Everything runs in your browser.
Like most tools on UtilityBase, the cipher encoder & decoder runs entirely in your browser — nothing you enter is uploaded or stored on a server. It's free to use with no account required. Browse more text tools here.
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