Image'n That

Written by ysf

The second crypto challenge points out that an an algorithm, even if known for it’s cryptographic rubustness, may leak information if you use it in a wrong mode:

My buddy claims that the safest way to encrypt his secret images with the secure AES-ECB algorithm. Can you prove him wrong?

!(Embed image here)[encrypted.png]

First I thought that some pixel substitional work would be needed, but after opening the image with feh I could read the flag, after remembering this years flag-format gigem{...}, almost instantly:

GIGEM{THE WORLD IS IN THE EYE OF THE BEHOLDER}

Which solved this challenge.

If this is new to you, I urge you to visit wikipedia for more information about ECB and other modes.