Quote:Original post by Codeka

Quote:Original post by RogerThat123
But what are these random areas where you put random junk in?

Can you give me an example?

Well, you can put extra data at the end of an exectuable and it is just ignored, so the simplest solution would be to write 100 (or so) bytes of random data to the end of the executable. A naive CRC check would change everytime you change that last 100 bytes.

But that doesn't actually solve the problem, because a hacker will just perform the CRC check on everything but that last 100 bytes.

You can get more tricky with where in the executable you write your random stuff, but where ever you write it, it's basically the same for the hacker - just exclude that area when they do their CRC check.

char buffer[100];	for(int i = 0; i < 100; i++)	buffer = rand();	HANDLE h = ::CreateFile("Test.dll", GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);	OVERLAPPED osWrite = {0};	DWORD dwWritten;	::SetFilePointer(h, 0, 0, FILE_END);	::WriteFile(h, buffer, 100, &dwWritten, &osWrite);	::CloseHandle(h);

Quote:Original post by godsenddeath
maybe try using blocks of random variables (say a block consists of 10 ints) that are initialized randomly on load.

That could possibly change the CRC

int random[10];for (i= 0; i < 10; i++)   random = rand()%100;