Rating:
100 points - 42 Solves
The Big Bad Wolf has entered the ring. He can HUFF, he can puff, but can he blow this house down?
Here is the original image.
Given the hint and the content of the file, we can deduce that this is a Huffman Coding problem. We can expect the flag to be hidden in a binary sequence somewhere in the image.
Using stegsolve we were able to find a message hidden on the left side of the file in the red, green, and blue channels.
I wrote a quick python program to extract the LSB of the red channel from the image.
from PIL import Image
bmp = Image.open("red0.bmp")
rgb_bmp = bmp.convert("RGB")
for i in range(0, 256):
r, g, b = rgb_bmp.getpixel((i, 0))
print(r & 1, end="")
print()
and obtained the binary sequence
0000010100101101000010011010001010100011010101001100101000101100110001110111111001100111011111000000111100010010110011001111101010001100011111011111111...
if we use the given Huffman tree to decode the sequence we get the flag.
