Get product key of windows machine through powershell

function Get-ProductKey {
     <#  
   
    .EXAMPLE
     Get-ProductKey -Computername Server1
    

        Retrieves the product key information from 'Server1'
    #>        
    [cmdletbinding()]
    Param (
        [parameter(ValueFromPipeLine=$True,ValueFromPipeLineByPropertyName=$True)]
        [Alias("CN","__Server","IPAddress","Server")]
        [string[]]$Computername = $Env:Computername
    )
    Begin {  
        $map="BCDFGHJKMPQRTVWXY2346789"
    }
    Process {
        ForEach ($Computer in $Computername) {
            Write-Verbose ("{0}: Checking network availability" -f $Computer)
            If (Test-Connection -ComputerName $Computer -Count 1 -Quiet) {
                Try {
                    Write-Verbose ("{0}: Retrieving WMI OS information" -f $Computer)
                    $OS = Get-WmiObject -ComputerName $Computer Win32_OperatingSystem -ErrorAction Stop               
                } Catch {
                    $OS = New-Object PSObject -Property @{
                        Caption = $_.Exception.Message
                        Version = $_.Exception.Message
                    }
                }
                Try {
                    Write-Verbose ("{0}: Attempting remote registry access" -f $Computer)
                    $remoteReg = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey([Microsoft.Win32.RegistryHive]::LocalMachine,$Computer)
                    If ($OS.OSArchitecture -eq '64-bit') {
                        $value = $remoteReg.OpenSubKey("SOFTWARE\Microsoft\Windows NT\CurrentVersion").GetValue('DigitalProductId4')[0x34..0x42]
                    } Else {                       
                        $value = $remoteReg.OpenSubKey("SOFTWARE\Microsoft\Windows NT\CurrentVersion").GetValue('DigitalProductId')[0x34..0x42]
                    }
                    $ProductKey = "" 
                    Write-Verbose ("{0}: Translating data into product key" -f $Computer)
                    for ($i = 24; $i -ge 0; $i--) {
                      $r = 0
                      for ($j = 14; $j -ge 0; $j--) {
                        $r = ($r * 256) -bxor $value[$j]
                        $value[$j] = [math]::Floor([double]($r/24))
                        $r = $r % 24
                      }
                      $ProductKey = $map[$r] + $ProductKey
                      if (($i % 5) -eq 0 -and $i -ne 0) {
                        $ProductKey = "-" + $ProductKey
                      }
                    }
                } Catch {
                    $ProductKey = $_.Exception.Message
                }       
                $object = New-Object PSObject -Property @{
                    Computername = $Computer
                    ProductKey = $ProductKey
                    OSDescription = $os.Caption
                    OSVersion = $os.Version
                }
                $object.pstypenames.insert(0,'ProductKey.Info')
                $object
            } Else {
                $object = New-Object PSObject -Property @{
                    Computername = $Computer
                    ProductKey = 'Unreachable'
                    OSDescription = 'Unreachable'
                    OSVersion = 'Unreachable'
                } 
                $object.pstypenames.insert(0,'ProductKey.Info')
                $object                          
            }
        }
    }
}