Recently Updated
Pixels
Challenge
mystery1:
mystery2:
Solution
Subtract pixel values from each other (and clean up output little bit more) reveals the flag:
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from PIL import Image
img1=Image.open("mystery1.png")
img2=Image.open("mystery2.png")
pixels1=img1.load()
pixels2=img2.load()
(width,height)=img1.size
## create new image to which we will write hidden image
outimg = Image.new( 'RGB', (width,height), "white")
pixels_out = outimg.load()
for w in range (0,width):
for h in range (0,height):
r=pixels1[w,h][0]-pixels2[w,h][0]
g=pixels1[w,h][1]-pixels2[w,h][1]
b=pixels1[w,h][2]-pixels2[w,h][2]
if (r,g,b)==(0,0,0) or (r>250 and g >250 and b >250) :
pixels_out[w,h] = (255,255,255)
else:
pixels_out[w,h] = (0,0,0)
outimg.save("outimpg.png","png")
Flag
easyctf{pretty_pixel_math}