Decent torrent sites will list whether the downloader requires a password of any kind. There's lots of torrent sites around.

If you downloaded a video via gnutella network, not via a torrent, & the video is encrypted, I'd be highly suspicious of it. If it were a RAR file, I'd also be suspicious of it. Only RAR videos from torrent sites are worth pursuing in general.

Check the filename. See if it corresponds with any on these filter lists: Direct instructions to eliminate porn & other marketing junk from results. Many of these keyword filter words will save you a lot of trouble.

Besides that, I do not recommend using LW for torrents. Better to use a torrent specific only program such as either uTorrent or Vuse (Azureus).