Comments on: Unique computer ID

By: Yair Altman

Yair Altman — Mon, 13 Jun 2022 09:41:08 +0000

@Mitchell – in most cases the user wants a single string identifier for the computer, that uniquely identifies it with a distinct fingerprint that is different from any other computer. The network interface (MAC) addresses are reported by the operating system, and naturally change when you add or remove a network card or adapter. It is up to you to decide which of the MAC addresses should be included in the fingerprint: if you include all of them, it certainly makes your fingerprint unique, but might include addresses that change frequently (e.g. VPN, WiFi, or virtual interfaces). On the other hand, if you ignore too many interfaces, your SID might be easier to spoof. Different operating systems have different ways of handling network interface MAC addresses, and you should consider this as well. For example, Windows and Linux addresses are pretty stable, but MacOS constantly changes the addresses when you connect/disconnect a network interface. MacOS also changes the computer’s hostname automatically, without any user approval, which is a PITA. In short, having a stable, unique SID that is less prone to spoofing requires some thought. If you need my assistance with this, please contact me privately (altmany at gmail).

By: Mitchell

Mitchell — Mon, 13 Jun 2022 00:58:39 +0000

Great post! I’m not very familiar with the network interfaces being referenced here, but it seems like the java-based cross-platform method concatenates all network interfaces. Does that mean that the SID returned by this method will change if a network interface is added or removed? Is it even possible to add or remove this type of network interface? Thanks!

By: Xiangrui Li

Xiangrui Li — Mon, 01 May 2017 20:06:18 +0000

Here is my practice for regexp. For all OS, always take the first mac_add pattern in the string output.

if ispc
    [~, a] = system('getmac');
    mac_add = regexp(a, '([0-9A-F]{2}-){5}[0-9A-F]{2}', 'match', 'once');
elseif isunix % OSX and Linux
    [~, a] = system('ifconfig');
    mac_add = regexp(a, '([0-9a-f]{2}:){5}[0-9a-f]{2}', 'match', 'once');
else
    mac_add = [];
end

By: Jeff E Mandel MD MS

Jeff E Mandel MD MS — Mon, 31 Oct 2016 13:41:06 +0000

Newer Macs have a hardware UUID. Note that Apple won’t allow a program that uses this in the App Store, but this probably won’t affect too many people writing deployed applications. Here is a little routine that accesses the system profile using the system_profiler command.

function profile = getMacProfile
% Retrieves all of the information from the OSX system profile and returns
% it in a structure, replacing spaces with underscores in the names and
% removing the attributes in parentheses.
 
[~,out]=system('system_profiler SPHardwareDataType');
theLines = splitlines(out);
for i = 1:length(theLines)
    if ~isempty(theLines{i})
        try
            c=strsplit(theLines{i},': ');
            if length(c) == 2
                d=strip(c{1});
                e=regexprep(d,' \(.*\)','');
                tag =strrep(e, ' ','_');
                profile.(tag) = c{2};
            end
        catch
            % In case Apple comes up with a new entry
            disp(theLines{i});
        end
    end
end

The UDID (unique device ID) is returned in profile.Hardware_UUID. This is probably more reliable than the MAC address of EN0.

By: Yair Altman

Yair Altman — Thu, 20 Feb 2014 17:20:36 +0000

Next time don’t post on a public blog something that you don’t want to appear publicly!

By: thomas

thomas — Thu, 20 Feb 2014 17:09:44 +0000

oh, i see.. the new method indeed gives .00000000000000E0.50E54950537A

thank you for your clarification. could you please delete my mac addresses, they were not intended to go public

By: Yair Altman

Yair Altman — Thu, 20 Feb 2014 16:56:43 +0000

@Thomas – it’s simply a different representation of the data. Here’s an implementation that should return more legible results:

ni = java.net.NetworkInterface.getNetworkInterfaces;
macStrs = {};
while ni.hasMoreElements
    macAddr = ni.nextElement.getHardwareAddress;
    if ~isempty(macAddr)
        macAddrStr = ['.' sprintf('%02X',mod(int16(macAddr),256))];
        macStrs{end+1} = macAddrStr; %#ok
    end
end
macStrs = sort(unique(macStrs));
sid = [macStrs{:}];

By: thomas

thomas — Thu, 20 Feb 2014 16:40:03 +0000

Yes, they are different, this is why i am confused a bit. The SID method gives .D6CDDF05903C.8888888600000000.8888888600000000.8888888600000000
IPconfig says:
50-E5-49-50-53-7A (this is the ethernet adapter)
00-00-00-00-00-00-00-E0
00-00-00-00-00-00-00-E0
00-00-00-00-00-00-00-E0

By: Yair Altman

Yair Altman — Thu, 20 Feb 2014 16:29:31 +0000

@Thomas – in this case you have 4 separate MAC addresses, from 4 separate network devices. Run the following in your Matlab command prompt to see the list (look at the “Physical Address” rows):

system('ipconfig /all')

This again is only unique if the user does not fool around with the MACs…

By: thomas

thomas — Thu, 20 Feb 2014 16:26:30 +0000

@Yair – sorry, I meant not SID but that second method, where sid = .89ECC872C85C.8AFE928FEDB4.8262278A1CCA.899919B50FC9

Is it the MAC address? Because MAC address has 12 digits. My SID (this 48 digits long) is different from my MAC. Thanks.

By: Yair Altman

Yair Altman — Thu, 20 Feb 2014 16:23:31 +0000

Thomas – of course: any computer-generated id can be spoofed and hacked. You can never fully protect yourself from this. But if you’re looking at normal legal behavior, then it should be unique for any practical purposes.

By: thomas

thomas — Thu, 20 Feb 2014 15:50:32 +0000

How unique is SID? Can be there 2 identical SIDs in the world?

By: Sami

Sami — Fri, 01 Mar 2013 11:10:11 +0000

Thanks for the code, it’s very helpful, however in the {‘win32′,’win64’} i had to add “+1” to get the right MAC address. without the preceding “=” :

mac_add = a(b(end)+1:b(end)+19);

By: Priti

Priti — Wed, 20 Feb 2013 14:33:56 +0000

really helpful

By: damayi

damayi — Wed, 23 May 2012 03:43:21 +0000

SID is not an absolutely secure way to protect your license.
There are many software tool which can modify computer sid, such as NewSid software.

By: itrentals

itrentals — Mon, 30 Apr 2012 12:46:15 +0000

This is a really good guide, especially for those developing software (like you say) who are fearful that it will get copied.

By: Jayveer

Jayveer — Wed, 16 Nov 2011 08:24:07 +0000

switch computer('arch')
    case {'maci','maci64'}
        [~,a]=system('ifconfig');
        c=strfind(a,'en0');if ~isempty(c),a=a(c:end);end
        c=strfind(a,'en1');if ~isempty(c),a=a(1:c-1);end
        % find the mac address
        b=strfind(a,'ether');
        mac_add=a(1,b(1)+6:b(1)+22);
    case {'win32','win64'}
        [~,a]=system('getmac');b=strfind(a,'=');
        mac_add=a(b(end):b(end)+19);
    case {'glnx86','glnxa64'}
        [~,a]=system('ifconfig');b=strfind(a,'Ether');
        mac_add=a(1,b(1)+17:b(1)+33);
    otherwise,mac_add=[];
end

By: Yair Altman

Yair Altman — Tue, 20 Sep 2011 22:35:35 +0000

@Matthias – thanks The code I posted above does exactly what you say, specifying the MAC addresses of all the computer’s network controllers. Please take a look – it’s actually quite simple and does not require any DLL, so it works on both Windows and non-Windows platforms.

By: Matthias

Matthias — Tue, 20 Sep 2011 22:21:46 +0000

Hi,

for licensing I always use the MAC address of (one of) the network controllers. This address is absolutley unique for each network device worldwide.

The only way to access this I know of is using C/C++ compiled to a *.dll which can then be called from MATLAB using calllib

If interested I can post the code from the function to access the device.

And yes, this is a great site, learned a lot about Java in MATLAB and using lots of it.
Keep up Yair!

Matthias

By: Yair Altman

Yair Altman — Wed, 20 Jul 2011 19:06:05 +0000

@Jan – I humbly stand corrected