ImaginaryCTF 2023 - Blurry
tl;dr:
Gaussian blurring is reverisble, oops!
Blurry
we are given a blurry image of an QR code - we probably need to undo the blur
Since we are cheap fukerz we will go with https://www.gimp.org/, after some fiddling with the default sharpening tools we are not getting anywhere.
Let’s install some more complex sharpen filters https://gmic.eu/
Assuming a gaussian blur after fiddling with
Details -> Sharpen [Deblur]
we find the right blur radius 7.7
and just push the iterations of the deblur filter until we get something squarish and readable, just going by eye here since we know how a QR code should look and we get the flag.
ictf{blurR1ng_is_n0_m4tch_4_u_2ab140c2}