0x0 Cryptanalysis

mercredi 10 juillet 2019, 12:41  #1
Known plaintext - XOR
Kew
Kew
  • 2 posts

Hi,
I’ve downloaded the BMP file and I wasn’t expecting it to simply open with a picture editor so I used the PIL library from Python to try and open it.
But this doesn’t work and I have this error : "cannot identify image file ch3.bmp"
I would like to know if I have to find another way or if I’m doing something wrong.
Can you help me ?
Thanks !

vendredi 12 juillet 2019, 12:14  #2
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p374
  • 3 posts

Hey there ! Before you open the file with an editor, you must decrypt its data. Try to look into the encrypted data and see what you can find. Think what you can do with your findings and proceed. Hope that this will help you !

vendredi 12 juillet 2019, 17:51  #3
Known plaintext - XOR
Kew
Kew
  • 2 posts

Thanks for your answer, p374.
I know that the data is encrypted and that is why I mentioned that I didn’t try to display it (open it with an editor) but rather access it via python in order to analyze it.
When you say that I have to look into the encrypted data, can you explain how or with what tool ?
As I say, I tried with the PIL library and it didn’t word...
Can you give me a hint please ?
Thank you for your time

samedi 13 juillet 2019, 12:28  #4
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p374
  • 3 posts

Hello again,

open the file with the open function and then use the read function. Print the data and see what you can get. Can’t help you more on this one.