Should output the Windows product key

ConvertTo-ProductKey.ps1

function ConvertTo-ProductKey {
    [CmdletBinding()]
    param(
        [byte[]]$Key,
        [switch]$Validate
    )
    end {
        $KeyOffset = 52
        [char[]]$Chars = "BCDFGHJKMPQRTVWXY2346789"
        $KeyOutput = ""
        
        [int]$isWin8 = ($Key[66] / 6) -and 1
        $Key[66] = ($Key[66] -and 247) -or (($IsWin8)*4)

        for ($i = 24; $i -ge 0; $i--) {
            [int]$Current = 0
            for ($x = 14; $x -ge 0; $x--) {
                $Current = $Current * 256
                $Current += $Key[$X + $KeyOffset]
                $Key[$X + $KeyOffset] = [math]::floor($Current / 24)
                $Current = $Current % 24
            }
            
            $KeyOutput = "$($Chars[$Current])$($KeyOutput)"
        }

        if ($isWin8) {
            $ReplaceString = -join $KeyOutput[1..$Current]
            $KeyOutput = (-join $KeyOutput[1..$KeyOutput.Length]) -replace "^$ReplaceString", "$($ReplaceString)N"
            if ($Current -eq 0) {$KeyOutput = "N$($KeyOutput)"}
        }

        @(
            $KeyOutput.Substring(0,5)
            $KeyOutput.Substring(5,5)
            $KeyOutput.Substring(10,5)
            $KeyOutput.Substring(15,5)
            $KeyOutput.Substring(20,5)
        ) -join '-'
        
        if ($Validate) {
            $LastGroupShouldBe = (Get-CimInstance -Query 'Select PartialProductKey From SoftwareLicensingProduct Where Name LIKE "Windows%" AND LicenseStatus>0').PartialProductKey
            if ($LastGroupShouldBe -eq $KeyOutput.Substring(20,5)) {
                Write-Information "Calculated key matches PartialProductKey '$($LastGroupShouldBe)'"
            } else {
                Write-Error "Calculated key did not match PartialProductKey '$($LastGroupShouldBe)'"
            }
        }
    }
}

$RegPath = "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\"
[byte[]]$DigitalProductIDBytes = Get-ItemProperty $RegPath -Name DigitalProductId | % DigitalProductId
@{
    ProductName = Get-ItemProperty $RegPath -Name ProductName | % ProductName
    ProductID   = Get-ItemProperty $RegPath -Name ProductID | % ProductID
    ProductKey  = ConvertTo-ProductKey -Key $DigitalProductIDBytes
}