HDD serial number flipped every 2 bytes in Windows XP, Vista and 7 but not in Windows 8

Question

I need to get HDD serial number to use it as a key for licensing a software. I used diskid32 code in this url: http://www.winsim.com/d

Answer 1

Basically you're relying on data that's not strictly reliable to begin with. Drives may change over the lifetime of a computer; all the while getting exactly the right serial number isn't even important to your product.

One easy hack I can think of is to normalize the serial number, e.g. by sorting the digits; this will make more drives look alike, but I doubt it will become an issue.

Another way of looking at the problem is that the application should provision for serial number changes; the user could be informed about the licensing issue (for whatever reasons) and asked to contact the support department with a generated code (not necessarily the serial number itself). Given this code, support can then create a new license for the customer.

Answer 2

Just turn off the flip using the "flip" flag of the flibAndCodeBytes function when windows 8 or greater.

bool shoulFlipBytes = true;
if(IsWin8OrLater()) shouldFlipBytes = false;

flipAndCodeBytes(buffer,
                 descrip->SerialNumberOffset,
                 shouldFlipBytes,
                 serialNumber);

You can use this to check for windows version:

#include <windows.h>

bool IsWin8OrLater() {
    DWORD version = GetVersion();
    DWORD major = (DWORD) (LOBYTE(LOWORD(version)));
    DWORD minor = (DWORD) (HIBYTE(LOWORD(version)));

    return (major > 6) || ((major == 6) && (minor >= 2));
}

According to http://msdn.microsoft.com/en-us/library/ms724832%28VS.85%29.aspx (Thanks to ChrisV Determine if O/S is Windows 7)

Answer 3

I use the same approach (and same code) in my software licensing. Yes, Windows 8 for some reason is returning flipped values for this method, I can't say why (so I can't answer your question).

My solution is the one that you pointed out: Flip the values again. So, after calling the "flipAndCodeBytes", you could test if is a Windows 8 OS, and flip the values.

In my case, it's working now (I got the same values for Windows XP/Vista/7 and Windows 8).

Good luck!

Answer 4

Seem you have to check for windows version through API and add if() branch to your code if version is high enough

My devs found other problem with this method - that kind of IOCtl code relies on program is being run with administrator rights on Win7\Win8+. In cause of our software, it's service that is run with system rights and clients software that is strictly run with user rights

Answer 5

For licensing-checking purposes, you really don't care. All you need to know is that some configurations result in flipping, some don't, and it can change during the lifetime of a license.

So accept both variants:

string serial = get_serial();
if (license_check(serial)) {
    licensed = true;
    return;
}
serial = swap_bytes(serial);
if (license_check(serial)) {
    licensed = true;
    return;
}

(I see Raymond suggested this in a comment)

No fragile OS check, no worries about whether it failed to flip right when the user applied for the license. Just happy users.