Question 1

What's the difference between ROT13 and Caesar cipher?

Accepted Answer

ROT13 is a specific Caesar cipher with a shift of 13. Because the alphabet has 26 letters, applying ROT13 twice returns the original text — so it's its own inverse and frequently used to obfuscate spoilers online.

Question 2

Is Caesar cipher secure?

Accepted Answer

No. It's a classical cipher broken trivially by frequency analysis and was used in antiquity for light obscuring, not real security. Use it for puzzles, spoilers or teaching — never for sensitive data.

ROT13 / Caesar Cipher