How to Crush a Caesar Cipher

Julius Caesar might have conquered the ancient world, but his famous cipher has a massive, glaring weakness. If you intercept a scrambled Roman message, you don't need advanced mathematics or a captured spy to read it. You just need a little patience.

The secret to beating this code is recognizing its limit. Because there are only twenty-six letters in the alphabet, there are only twenty-five possible ways to shift them. That means there are exactly twenty-five possible keys to the entire system.

Code-breakers call this a "brute force" attack. You don't look for clever clues—you just kick the door down. Take the first scrambled word of the message and shift its letters backward by one space. If it is still gibberish, shift it by two. Then three.

Long before you test all twenty-five shifts, a normal, readable word will magically appear on your page. The Romans got away with this trick because most of their enemies couldn't read at all. Today, busting it open is the ultimate code-breaking superpower.