Shuffle

Description

country: Borneo

challenge

Solution

shuffle-1

If you take a closer look at broken image with hex editor (I use VSCode Hex Editor) and compare to any png image you'll notice that some bytes are swapped.

Let's say original is: 00 11 22 33 44 55 66 77, Corrupted image: 00 11 44 55 22 33 66 77

shuffle-2

Using this python script convert corrupted image to flag:

chunks = []
with open('./challenge.png', 'rb') as image:
    while (byte := image.read(2)):
        chunks.append(byte)


with open('./solve.png', 'wb') as png:
    swapped = False
    for i in range(len(chunks)):
        if i % 3 == 0 : # Skip every 3rd chunk
            png.write(chunks[i])
        elif swapped: # If already swapped ignore
            swapped = False
        else: # Do swap
            png.write(chunks[i+1])
            png.write(chunks[i])
            swapped = True 

shuffle-3

Flag: flag{come_and_pl4y_w1th_us}