Caesar Decoder

Julius Caesar is said to have protected his letters by shifting every letter a fixed number of places along the alphabet. The method is simple, fast and completely unsafe today, but it is the perfect first step into cryptography, because breaking it teaches the core idea of frequency and brute force.

The decoder shows you a ciphertext and a slider. Each position of the slider is a candidate shift, and the plaintext beneath updates as you move it. The shift setting for this lab is auto. Somewhere along the slider the gibberish turns into readable English, and inside that English is the flag.

There are only 25 sensible shifts, which is why the cipher is so weak. Any attacker can try all of them in seconds. Real ciphers work because their keys are too numerous to try, not because their method is secret.

Move the slider until the text makes sense. Copy the flag from the plaintext and submit it, including the wrapper.