WindowsRT Surface(Tablet) identifying

Question

How do I uniquely identify a surface(tablet)? How do I get id of a tablet? there is a way using `HardwareIdentification.GetPackageSpecificToken(null). The problem is, it changes for simple hardware changes like disabling bluetooth. Is there a way to get unique id for a tablet which never changes?

Answer 1

You can use HardwareIdentification.GetPackageSpecificToken(null), see http://msdn.microsoft.com/en-us/library/windows/apps/jj553431.aspx

That function gives you a lot of information, that you can filter as you like. For example:

using System.Runtime.InteropServices.WindowsRuntime;

public static string GetMachineId()
{
    var hardwareToken = 
        HardwareIdentification.GetPackageSpecificToken(null).Id.ToArray();
    var count = hardwareToken.Length / 4;
    ulong id = 0ul;
    for (int i = 0; i < count; i++)
    {
        switch (BitConverter.ToUInt16(hardwareToken, i * 4))
        {
            case 1:
                // processor
            case 2:
                // memory
            case 9:
                // system BIOS
                id = (id << 12) ^ BitConverter.ToUInt16(hardwareToken, i * 4 + 2);
                break;
        }
    }
    return Convert.ToBase64String(BitConverter.GetBytes(id));
}

However, bear in mind that this function, and the underlying API, cannot guarantee absolute uniqueness across all the machines connected to the internet. You would typically combine this with information about the user.

Another option is to generate and store a GUID in local (non-roaming) storage, and use that as your machine id. Depending in you exact needs, this may be a better solution.

UPDATE

The Guid method is fairly simple. Just generate a new Guid the first time the app is run using

Guid installationId = Guid.NewGuid();

Then store that in a local file using

StorageFile file = await ApplicationData.Current.LocalFolder.CreateFileAsync(
    "installationId", 
    CreationCollisionOption.FailIfExists);

using (Stream fileStream = await file.OpenStreamForWriteAsync())
{
    await fileStream.WriteAsync(installationId.ToByteArray(), 0, 16)
    await fileStream.FlushAsync();
}

On subsequent runs, you detect that the file is there and read it.

A possible disadvantage of this method is that, when the application is uninstalled and subsequently reinstalled, a new GUID will be generated.