Help with Hardware ID

Question

I'm using C# and .NET 2.0. My app needs some way to check the different users so I'll use hardware id, but I saw that I can use only:

• mac address - easily changeable and not everybody have it // NO
• processor id - using WMI it returns a value for the cpu model, it's not unique // NO
• motherboard serial - not every motherboard have it // NO
• the Windows's volume serial - I'm not sure if it will be changed on Windows reinstall and format of the volume

So is there something I didn't mention for hwid? I want something that everybody have and it won't be erased on windows reinstall. Else I'd have to use the windows's volume serial number.

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EDIT: From the commments I think it's best to use HDD id. How to get it? EDIT2: I just read that the SCSI drives don't have serial. Is that true?

Answer 1

HDD Serial number: unique, unchangeable, and everyone has it.

not a perfect option but...

Answer 2

Well i'd go for more than one id. If you combine enough IDs they will get you enough uniqueness.

EDIT: you might also go for the place on the harddisk your program was installed too (Platter, Cylinder etc.)

Answer 3

Why do you want to use hardware Id? I'd go with some kind of forms-based (or AD based) security, myself.

Given that, however: The thing about HWID is that it identifies that particular computer configuration: it is designed to change if there are system changes. You mention that Windows Volume Serial could change on reinstall and reformat, but won't your software also have to be reinstalled at that point? HDD Serial could also change if, say, the user swaps HDDs for some reason.

If you have to use HWID, you'll probably need to select one (or more) of the available options to provide uniqueness and either code around, or inform users about, hardware changes requiring a re-install and/or reconfigure of your software.