Trip to space

Aperi'CTF 2019 - Steganography (50 pts).

Aperi’CTF 2019 - Trip to space

Challenge details

Event Challenge Category Points Solves
Aperi’CTF 2019 Trip to space Steganography 50 38

Votre lecteur d’image vous ment-il ?

Challenge: - md5sum : a93693fb6f6ebc813510e60582e9d8d3


Open it !

Open the image in a web browser or in a decent image viewer.

Gnome, Mobile, Windows… : bug.jpg

Web browser, MAC, … : ok.jpg


Some image viewer implement gamma correction. This correction has a real impact on the image (here, the flag is displayed or not).

Fore more information about gamma correction and gamma steganography: - Gamma steganography - Gamma error in picture scaling