C / C++ / MFC

Naveen3-Jul-07 14:01

3-Jul-07 14:01

A simple example. Suppose I cut first 10 bytes of exe and put at the end of the file. Then the exe will not be executable isnt't it? So after extracting I should roll back this changes, means i copy the last 10 bytes and put it in the begining. then execute the exe.

nave

[OpenedFileFinder]

Rationalise3-Jul-07 15:08

3-Jul-07 15:08

Well but in executing it, unless we run in from memory straight, the user could still copy the correct exe while it's running. Doesnt solve the problem?

Naveen3-Jul-07 15:16

3-Jul-07 15:16

I have foudn some applications like ie creates some temp file while browsing some sites( for ex if you took a video in the youtube, you can see a "temp" file created in the temporary internet folder.I noticed that that file cannot be renamed or copied or deleted. If we kill the IE, that files get deleted automatically. May be you implement the same technique. I dont know how IE does this. If you got any information, tell me also.

Other option is to make a loader by your self.May be very difficult.I shall inform you if i got any other solutions.

nave

[OpenedFileFinder]

Rationalise3-Jul-07 15:23

3-Jul-07 15:23

Ok man cool.
I'll look into that option. Smile | :)

Ya loader is very hard to do.. I wonder how the commercial exe protecter do it.

Naveen3-Jul-07 15:33

3-Jul-07 15:33

Rationalise wrote:
I wonder how the commercial exe protecter do it.

hmm..a matter to investigate..

nave

[OpenedFileFinder]

Naveen3-Jul-07 17:28

3-Jul-07 17:28

Got the way. Create the file using the flag FILE_FLAG_DELETE_ON_CLOSE Smile | :)

nave

[OpenedFileFinder]

Rationalise3-Jul-07 20:27

3-Jul-07 20:27

Hmm interesting. Only I'm using c# so cannot use CreateFile. File.Create does not offer such an option.
I'm looking into other methods of limiting access rights, so the file cannot be copied.

Naveen3-Jul-07 20:44

3-Jul-07 20:44

Rationalise wrote:
other methods of limiting access rights

Limiting access will not do. Because under such cases, if your application is terminated using the taskmanger, all the access limits will be removed.

nave

[OpenedFileFinder]

Rationalise3-Jul-07 23:07

3-Jul-07 23:07

What we need is to prevent copying of the exe. But it seems that it cannot be done from what i read.
I've changed to researching on modifying the PE itself and injecting my own license checking codes. Shall get back to you if I have anything.

led mike5-Jul-07 4:24

led mike

5-Jul-07 4:24

Naveen.R wrote:
Suppose I cut first 10 bytes of exe and put at the end of the file.

that's what you call encryption? Confused | :confused:

Naveen.R wrote:
add some encrytption

Naveen5-Jul-07 14:01

5-Jul-07 14:01

led mike wrote:
that's what you call encryption?

At the Simplest.Also we just an example. Unless u know that i had moved the first 10 bytes, Will you be able to make it correct again?

nave

[OpenedFileFinder]

led mike6-Jul-07 5:59

led mike

6-Jul-07 5:59

Naveen.R wrote:
At the Simplest

That's just "wrong". What you are prescribing is called "obfuscation" it is NOT "encryption".

Naveen6-Jul-07 20:20