Function Extract-Rid([byte[]] $sid) {
  $sid_length = $sid.Count
  $sid[$sid_length - 4] + 256 * $sid[$sid_length - 3] + 65536 * $sid[$sid_length - 2] + 16777216 * [uint32]$sid[$sid_length - 1]
}

Function Is-SystemUserSid([byte[]] $sid) {
    if (($sid.Count -eq 28) -and ($sid[0] -eq 1) -and ($sid[1] -eq 5) -and ($sid[7] -eq 5) -and ($sid[8] -eq 21)) {
      $rid = Extract-Rid($sid)
      ($rid -lt 1000)
    } else {
      $FALSE
    }
}

Function Is-SystemGroupSid([byte[]] $sid) {
    ($sid.Count -eq 16) -and ($sid[0] -eq 1) -and ($sid[1] -eq 2) -and ($sid[7] -eq 5) -and ($sid[8] -eq 32)
}

$users_and_groups = Import-Csv -Path "users_and_groups.txt" -Delimiter "`t" -Encoding UTF8
$users = $users_and_groups | Where-Object { $_.Type -eq "user" } | foreach { $result = @{} } { $result[$_.RID.ToString()] = $_ } { $result }
$groups = $users_and_groups | Where-Object { $_.Type -eq "group" } | foreach { $result = @{} } { $result[$_.RID.ToString()] = $_ } { $result }
$computer = [ADSI] "WinNT://."
$computer.Children.SchemaFilter.Clear()
$computer.Children.SchemaFilter.AddRange(@("user", "group"))
$computer.Children | foreach {
    $sid = $_.objectSid[0];
    $rid = (Extract-Rid($sid)).toString()
    if (Is-SystemUserSid($sid) -and $users.Contains($rid)) {
      $user = $users[$rid];
      Write-Host ("Updating user `"" + $_.Name.Value + "`" with new name `"" + $user.Name + "`" and description.")
      $_.Rename($user.Name)
      $_.Description = $user.Description
      $_.CommitChanges()
    } elseif (Is-SystemGroupSid($sid) -and $groups.Contains($rid)) {
      $group = $groups[$rid];
      Write-Host ("Updating group `"" + $_.Name.Value + "`" with new name `"" + $group.Name + "`" and description.")
      $_.Rename($group.Name)
      $_.Description = $group.Description
      $_.CommitChanges()
    }
  }