Encoding
ROT13 / Caesar Cipher
Caesar cipher — a cyclic shift of Latin alphabet letters. ROT13 is the special case with shift 13 (button below), symmetric: encode and decode give the same result. Other characters (digits, punctuation, non-Latin letters) are left unchanged.
Frequently asked questions
Is ROT13 actually secure?
No, not at all. ROT13 is a trivial letter-rotation cipher with no real security — anyone can decode it instantly, even by eye. It's used for obfuscating spoilers or puzzle answers, not for protecting sensitive data.
Why does encoding and decoding give the same result for ROT13?
ROT13 shifts letters by 13, exactly half of the 26-letter alphabet, so applying it twice returns the original text — encode and decode are the same operation.
What happens to numbers, punctuation, or non-Latin letters?
They're left unchanged. Only Latin alphabet letters are shifted; the custom shift value works the same way for any Caesar cipher variant.