Caesar Cipher
Encode and decode messages with the Caesar Cipher. Choose the shift (1–25) and convert text instantly in the browser.
What is the Caesar cipher?
The Caesar cipher is one of the oldest encryption techniques on record, used by Julius Caesar to protect military dispatches. Each letter of the text is shifted N positions along the alphabet. With a shift of 13 it is known as ROT13. Only letters are affected — digits, spaces and symbols pass through unchanged.
Caesar cipher: encode and decode
Attributed to the Roman emperor, the Caesar cipher is one of the oldest known encryption techniques. It works by sliding each letter a fixed number of positions through the alphabet. This tool encodes and decodes messages with that cipher, in both directions.
Pick the shift, from 1 to 25, and the text converts right away. You can solve and create puzzles, take on CTF challenges, play with secret messages or study the fundamentals of cryptography. One caveat, though: precisely because it's so simple, the cipher is easy to break, so it's meant for fun and learning, never for protecting real information.
The conversion happens in your browser and the text never leaves it. Set the shift, paste the message and the result shows up next.
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