Shift every letter by a fixed number of places, or try every shift to find the hidden message.
The Caesar cipher replaces each letter with the one a set number of places further along the alphabet, wrapping from Z to A. Case is kept and non-letters are left as they are. Choose a shift and whether to encrypt or decrypt.
The brute force view prints all 25 possible shifts as a list. Because there are so few keys, reading down the list until one line makes sense is the quickest way to break an unknown Caesar message.
No. With only 25 useful keys it can be broken by trying them all. It is for fun and teaching, not for protecting anything.
Choose the show all shifts mode. One of the 25 lines will be readable text, and its shift number is the key.
A Caesar cipher with a shift of 13. Because the alphabet has 26 letters, applying it twice returns the original text.