What is the Caesar cipher?

The Caesar cipher shifts each letter in the text by a fixed number of positions (1–25) in the alphabet. For example, with a shift of 3: A→D, B→E, Z→C. It is one of the oldest encryption methods.

ROT13 is a special Caesar cipher with a shift of exactly 13. Since the alphabet has 26 letters, applying ROT13 twice returns the original text. A→N, B→O, N→A, etc.

Is Vigenère cipher secure?

The Vigenère cipher is stronger than Caesar cipher but is still breakable with modern techniques (Kasiski examination, frequency analysis). It is not suitable for real security — use AES or other modern encryption for actual security needs.

Text Encryption & Decryption — Caesar, ROT13, Atbash, Vigenère

How to Use Text Encryption & Decryption

1
Select Encrypt or Decrypt mode.
2
Choose your cipher: Caesar, ROT13, Atbash, or Vigenère.
3
For Caesar cipher, set the shift value (1–25) using the slider.
4
For Vigenère cipher, enter your keyword (letters only).
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Type your text and see the result appear instantly. Use the Copy button to copy the output.

About Text Encryption & Decryption

The Text Encryption & Decryption tool lets you encode and decode text using four classic cipher techniques: Caesar cipher, ROT13, Atbash, and Vigenère cipher. All processing happens in your browser — your text is never sent to any server.

Caesar Cipher

One of the oldest and simplest encryption methods, used by Julius Caesar. Each letter is shifted by a fixed number of positions in the alphabet (1–25). A shift of 13 is the special case known as ROT13.

ROT13

ROT13 ("rotate by 13 places") is a Caesar cipher with a fixed shift of 13. Applying ROT13 twice returns the original text, making it its own inverse. Historically used to hide spoilers and off-topic content in online forums.

Atbash Cipher

An ancient Hebrew cipher where A↔Z, B↔Y, C↔X, etc. — the alphabet is reversed. Like ROT13, applying it twice returns the original.

Vigenère Cipher

A polyalphabetic cipher using a keyword. Each letter of the plaintext is shifted by the corresponding letter of the keyword, making it much harder to crack than simple Caesar ciphers. Considered unbreakable for centuries.

Text Encryption & Decryption