Re: xorpng

On a sunny day (Mon, 6 Jan 2025 19:49:01 +0100) it happened Stefan Claas
<pollux@tilde.club> wrote in <vlh8it$14fe4$1@paganini.bofh.team>:

Stefan Claas wrote:

Stefan Claas wrote:

Rich wrote:

Stefan Claas <pollux@tilde.club> wrote:

*Please* try to write a .ppm (P6) to .png converter (and back) in C(++)
and see if you can get the *original* data back. The sci.crypt community
and me of course would appreciate your help very much!

 
Since you have not "shown your work" (apologizes if you show it later,
I'm replying as I encounter articles in date order) we can't help you
diagnose your problem.

 

So, to the extent I can tell, you are doing something wrong somewhere.

 
Please try your conversion steps with the encrypted image, I already
have shown:
 
https://jmp.sh/HZM9ML9f
 
It includes a padding byte, needed for ppm so that it is divideable by 3.

 
Welln ot true, but the paading byte causes the issue, because it gets
lost when converting.

>
I will use encryption and then file2png, which makes the noise image
smaller in size, compared to the original image.
>
https://github.com/706f6c6c7578/file2png

All nice stuff, but an image with just noise makes one suspicious..
and than have a go at hacking it perhaps

Somehow embed the noise in a real image, like one looking at a TV with noise..
'my TV failed'
Bit more complicated to code... sub=area of the image.