ROT13 Encoder/Decoder
Encode or decode text using ROT13 cipher. Symmetric — same operation encodes and decodes.
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ROT13 output appears automatically as you type
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ROT13 Encoder: Understanding the Simplest Letter Substitution Cipher
Learn how ROT13 works, why it is symmetric, and where this simple cipher is still used today.
What Is ROT13?
ROT13, short for "rotate by 13 places," is a simple letter substitution cipher that replaces each letter in a text with the letter 13 positions ahead in the alphabet. It is a special case of the Caesar cipher, one of the oldest known encryption techniques. Because the Latin alphabet has 26 letters, applying ROT13 twice returns the original text — making it perfectly symmetric.
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