Windows

(Get-WmiObject -query "select * from SoftwareLicensingService").OA3xOriginalProductKey

function GetWin10Key {

    $Hklm = 2147483650

    $Target = $env:COMPUTERNAME

    $regPath = "Software\Microsoft\Windows NT\CurrentVersion"

    $DigitalID = "DigitalProductId"

    $wmi = [WMIClass]"\\$Target\root\default:stdRegProv"

    # Get registry value 

    $Object = $wmi.GetBinaryValue($hklm, $regPath, $DigitalID)

    [Array]$DigitalIDvalue = $Object.uValue 

    # If get successed

    if($DigitalIDvalue) {

        # Get producnt name and product ID

        $ProductName = (Get-itemproperty -Path "HKLM:Software\Microsoft\Windows NT\CurrentVersion" -Name "ProductName").ProductName 

        $ProductID =  (Get-itemproperty -Path "HKLM:Software\Microsoft\Windows NT\CurrentVersion" -Name "ProductId").ProductId

        # Convert binary value to serial number 

        $Result = ConvertTokey $DigitalIDvalue

        $OSInfo = (Get-WmiObject "Win32_OperatingSystem"  | select Caption).Caption

        if($OSInfo -match "Windows 10") {

          if($Result) {

            [string]$value ="ProductName  : $ProductName `r`n" `

            + "ProductID    : $ProductID `r`n" `

            + "Installed Key: $Result"

            $value

          }

        }

        else { Write-Warning "Run in Windows 10 only" }

    }

    else { Write-Warning "Error reading key" }

}

# Convert binary to serial number 

function ConvertToKey($Key) {

    $Keyoffset = 52 

    $isWin10 = [int]($Key[66]/6) -band 1

    $HF7 = 0xF7

    $Key[66] = ($Key[66] -band $HF7) -bOr (($isWin10 -band 2) * 4)

    $i = 24

    [String]$Chars = "BCDFGHJKMPQRTVWXY2346789" 

    do {

        $Cur = 0; $X = 14

        do {

            $Cur = $Cur * 256    

            $Cur = $Key[$X + $Keyoffset] + $Cur

            $Key[$X + $Keyoffset] = [math]::Floor([double]($Cur / 24))

            $Cur = $Cur % 24

            $X = $X - 1 

        } while($X -ge 0)

        $i = $i - 1

        $KeyOutput = $Chars.SubString($Cur, 1) + $KeyOutput

        $last = $Cur

    } while($i -ge 0)

    $Keypart1 = $KeyOutput.SubString(1, $last)

    $Keypart2 = $KeyOutput.Substring(1, $KeyOutput.Length - 1)

    if($last -eq 0 ) {

        $KeyOutput = "N" + $Keypart2

    }

    else {

        $KeyOutput = $Keypart2.Insert($Keypart2.IndexOf($Keypart1) + $Keypart1.Length, "N")

    }

    $a = $KeyOutput.Substring(0,5)

    $b = $KeyOutput.Substring(5,5)

    $c = $KeyOutput.Substring(10,5)

    $d = $KeyOutput.Substring(15,5)

    $e = $KeyOutput.Substring(20,5)

    $keyproduct = $a + "-" + $b + "-"+ $c + "-"+ $d + "-"+ $e

    $keyproduct 

}

GetWin10Key