On Sat, 26 Jun 2004, markus wrote:
I have an application that I think was developed using some form of
Borland C with a folder for BIG images with the extension .fre. When I
try to view them they cannot be read even by changing the extension
to jpg, bmp, zip, etc.
I also used some utilities for resource extraction with no success.
I know the images are there and there has to be a way to show and
convert them to a known format. I have seen libjpeg.dll and zlib.dll
in the main application folder along with other dlls.
Please suggest some utility or tell me the way developers usually hide
application jpg images (not icons, etc).
As a developer I have numerous ways of encrypting data. I can use a simple
Caesar cipher. I can reverse the data. I can flip the bits. I can store it
as char in memory but read/write it as long on a little endian machine
(flips every four bytes). The options are limitless.
Typically, performance and my imagination are the only things limiting how
I can encrypt the data. Obviously, I'm going to pick a method that is easy
to decrypt but that will not be obvious to someone looking at the data.
If might even encrypt the header information differently then the body. Or
I might just encrypt the header and leave the body unaltered.
Are you getting the idea? There is no standard way to do this. Being
non-standard is part of the security. Mystery makes your job harder so I'm
going to pick something that I have not seen before or I'm going to
combine two methods I have seen before to come up with something new.
More importantly, why would the developer use a non-standard format for
their image data? Could it be that they don't want you to decrypt the
images? By helping you wouldn't I be hurting the developer? Why wouldn't I
want to help the developer by not helping you?
I would hope that other developers would respect my choice to encrypt the
data and not help someone steal my images.
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