Secure Unique Computer ID

2024-05-30 12:00 UTC gpt-4o Open in ChatGPT ↗

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What is the most certain way to get a computer’s unique ID, so that i know when my VBA file is opened on another computer? The technique must be secure against most common ways of spoofing a machine. It needs to work on both macOS and WIndows, even if it means that 2 separate techniques must be used

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To achieve a secure and unique identification of a computer when your VBA file is opened, you can use different methods for macOS and Windows. Here are the techniques tailored for each operating system:

Windows: Using WMI (Windows Management Instrumentation)

On Windows, you can use WMI to retrieve the BIOS Serial Number or the Disk Drive Serial Number. These are difficult to spoof and provide a unique identifier for the machine.

Here’s how you can get the BIOS Serial Number using VBA:

Sub GetBIOSSerialNumber()
    Dim objWMIService As Object
    Dim colItems As Object
    Dim objItem As Object
    Dim strComputer As String
    Dim BIOSSerial As String

    strComputer = "."
    Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")
    Set colItems = objWMIService.ExecQuery("Select * from Win32_BIOS")

    For Each objItem In colItems
        BIOSSerial = objItem.SerialNumber
        Exit For
    Next

    MsgBox "BIOS Serial Number: " & BIOSSerial
End Sub

macOS: Using System Profiler

On macOS, you can use the system_profiler command to get the Hardware UUID, which is a unique identifier for the Mac.

Here’s how you can execute a shell command in VBA to retrieve the Hardware UUID:

Sub GetHardwareUUID()
    Dim shell As Object
    Dim command As String
    Dim result As String

    Set shell = CreateObject("WScript.Shell")
    command = "system_profiler SPHardwareDataType | awk '/Hardware UUID/ {print $3}'"
    result = shell.Exec("/bin/bash -c """ & command & """").StdOut.ReadAll

    MsgBox "Hardware UUID: " & Trim(result)
End Sub

Combining Both Methods

You can combine both methods in your VBA project and determine the operating system at runtime to execute the appropriate code. Here is an example of how you might structure this:

Sub GetUniqueID()
    If Application.OperatingSystem Like "*Mac*" Then
        GetMacHardwareUUID
    Else
        GetWindowsBIOSSerialNumber
    End If
End Sub

Sub GetWindowsBIOSSerialNumber()
    Dim objWMIService As Object
    Dim colItems As Object
    Dim objItem As Object
    Dim strComputer As String
    Dim BIOSSerial As String

    strComputer = "."
    Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")
    Set colItems = objWMIService.ExecQuery("Select * from Win32_BIOS")

    For Each objItem In colItems
        BIOSSerial = objItem.SerialNumber
        Exit For
    Next

    MsgBox "BIOS Serial Number: " & BIOSSerial
End Sub

Sub GetMacHardwareUUID()
    Dim shell As Object
    Dim command As String
    Dim result As String

    Set shell = CreateObject("WScript.Shell")
    command = "system_profiler SPHardwareDataType | awk '/Hardware UUID/ {print $3}'"
    result = shell.Exec("/bin/bash -c """ & command & """").StdOut.ReadAll

    MsgBox "Hardware UUID: " & Trim(result)
End Sub

Security Considerations

• Permissions: Ensure your VBA code has the necessary permissions to execute WMI queries on Windows and shell commands on macOS.
• Spoofing: While these methods are robust, no technique is entirely spoof-proof. Physical access to the machine and advanced knowledge could potentially bypass these checks.

This solution provides a strong foundation for identifying computers uniquely across both operating systems with VBA.