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Caesar Cipher

Caesar cipher encoder/decoder with custom shifts and ROT13.

Shift
steps
Input Text0 chars
Output0 chars

Alphabet Mapping

Current A → D
ABCDEFGHIJKLMNOPQRSTUVWXYZ
DEFGHIJKLMNOPQRSTUVWXYZABC

What is Caesar Cipher?

The Caesar cipher is one of the simplest and most widely known encryption techniques. It is a type of substitution cipher in which each letter in the plaintext is replaced by a letter some fixed number of positions down the alphabet.

For example, with a shift of 3, A would be replaced by D, B would become E, and so on.

The method is named after Julius Caesar, who used it in his private correspondence for military communication.

About This Tool

The Caesar cipher is a classic shift substitution cipher that rotates letters by a fixed offset. This tool supports both encode and decode modes with a 0-25 shift range, built-in ROT13 quick action, and options to preserve non-letters and letter case. All processing is done locally for speed and privacy.

Features

  • 🔄 Encode/Decode Modes: Bidirectional conversion with real-time output
  • 🎚️ Shift Control: 0-25 adjustable with quick shift actions
  • 🧩 Case & Symbol Handling: Preserve letter case and non-letters
  • 📋 Copy & Swap: One-click copy and input/output swap
  • 📚 Alphabet Mapping: Visualize the current shift rule