> For the complete documentation index, see [llms.txt](https://maurvan.gitbook.io/ctf-writeups/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://maurvan.gitbook.io/ctf-writeups/cyberweek-2024/index/ave-cesar.md).

# Ave César

## Challenge

> pgs{apuwuhbh89uwnoqycsrawY}

## Solution

Because of the title I figured this was a Caesar Cypher and I used [this website](https://www.dcode.fr/caesar-cipher) to decipher the code. It lists all possible shifts using the alphabet, giving me these results:

<figure><img src="https://1102212211-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fa46Jmz9dIuFnWcXn3ooO%2Fuploads%2FcoxGPg0ZuPshuYUgUfrj%2Fcaesar_list.png?alt=media&amp;token=40c94344-d4d8-4084-932f-48da84234258" alt=""><figcaption></figcaption></figure>

I knew the first 3 letters were "ctf" because this is the code for the flags they have been using, which means the 5th entry is the correct one.

## Additional information

The Caesar cipher is a classic example of ancient cryptography that involves shifting each letter of a plaintext message by a certain number of letters. It is a type of substitution cipher where one letter is substituted for another in a consistent fashion.

The method is named after Julius Caesar, who used it in his private correspondence.

Disk used to decrypt this cipher:

<figure><img src="https://1102212211-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fa46Jmz9dIuFnWcXn3ooO%2Fuploads%2F6vQMzPPGbK5FR7RsOE8j%2F1200px-CipherDisk2000.jpg?alt=media&amp;token=f11185e1-3afb-411c-b2ce-071908f227f1" alt=""><figcaption></figcaption></figure>
