Text Encryptor (Caesar / ROT13)

Encrypt and decrypt text with classic ciphers: Caesar shift, ROT13 and Atbash.

Related Tools

🔑
Hash Generator
Compute SHA-1, SHA-256, SHA-384 and SHA-512 hashes of any text in your browser.
 🧬
Base64 Encode / Decode
Encode any text to Base64 or decode a Base64 string back to plain text.
 🔣
HTML Entity Encoder / Decoder
Encode text to HTML entities or decode entities back to text.

0 comments

How it works

These are classic substitution ciphers that shift or swap letters. A Caesar cipher moves each letter a fixed number of places in the alphabet; ROT13 is a Caesar shift of 13, which is its own inverse. Atbash maps each letter to its mirror (A↔Z, B↔Y). Non-letters are left unchanged and case is preserved. Pick a cipher and shift, and the tool transforms your text instantly. These are for puzzles and learning, not real security — all processing runs in your browser.


              Caesar: c = (letter + shift) mod 26
ROT13 = Caesar shift 13

Common use cases

  • Solving or creating a Caesar-cipher puzzle.
  • Obscuring a spoiler or answer with ROT13.
  • Teaching how substitution ciphers work.

Frequently asked questions

Is this secure encryption?

No. Caesar, ROT13, and Atbash are classic ciphers that are trivially broken. They are great for puzzles, spoilers, and learning, but never use them to protect real secrets.

Why is ROT13 the same to encode and decode?

ROT13 shifts by 13, exactly half of the 26-letter alphabet. Applying it twice shifts by 26, returning to the original, so the same operation both encodes and decodes.

Does it change numbers and symbols?

No. Only letters are shifted; digits, spaces, and punctuation pass through unchanged, and letter case is preserved.