🔐 ROT13 & Caesar Cipher Converter

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Encrypt Spoilers and Decode Text with ROT13 & Caesar Ciphers

Encrypt and decrypt messages instantly using classic ROT13 and Caesar cipher methods. Whether you're hiding plot twists or learning the basics of cryptography, this tool handles the shift for you.

💡 How to Use This Tool

Hide movie spoilers on forums or create puzzles for friends by shifting letters in the alphabet by a set number of positions.

  • Protect Spoilers: Mask text on Reddit, Geocaching, or Discord so others only read it when they're ready.
  • Learn Cryptography: Explore the fundamentals of substitution ciphers, perfect for students and hobbyists.
  • Encode for Fun: Transform notes into secret codes that require a specific shift key to read.

📘 Pro Tips

  • Translate as You Type: See results instantly with real-time conversion—no "Submit" button required.
  • Customize Your Shift: Use the slider to select any variation from ROT1 to ROT25. ROT13 is the default, but any key works.
  • Maintain Structure: Numbers, punctuation, and spaces remain untouched, preserving your message's original formatting.
  • Copy and Share: Grab your encoded text with one click to paste it anywhere.

🧐 FAQ

How do I decrypt a ROT13 message? Because the English alphabet has 26 letters, shifting a letter by 13 positions twice brings you back to the start. Just paste the encrypted text back into the tool with the shift set to 13.

Does it support non-English characters? This tool is optimized for the standard Latin alphabet (A-Z). Symbols, numbers, and accented characters (like ñ or é) remain unchanged.

Is my data secure? Yes. All processing happens locally in your browser. Your text is never sent to or stored on any server.

📚 Trivia

Julius Caesar used this cipher with a shift of three to protect military communications. While basic by modern standards, it laid the foundation for all substitution-based cryptography.

ROT13 became the internet standard because it is "self-inverse"—the same operation encrypts and decrypts the text. It has been the go-to method for hiding spoilers in newsgroups and forums since the 1980s.