picoCTF 2023 – rotation

28 March 2023 – Written by Valentin Huber – in crypto, ctf, cyberchef, and rot13

Challenge

You will find the flag after decrypting this file Download the encrypted flag here.

File content:

xqkwKBN{z0bib1wv_l3kzgxb3l_429in00n}

Solution

The challenge title indicates some form of rotation cipher, so I put the encoded text into cyberchef and used the ROT13 Brute Force module to rotate the text. A quick text search on the output showed that the encoding is a rotation by 18 chars and the flag is picoCTF{r0tat1on_d3crypt3d_429af00f}.