You are still missing, or ignoring the fact that BitTorrent clients do NOT use or understand FILES and folders at the level you are considering. The file and directory structure is NOT important or even useful to a BitTorrent payload, neither is the SHA1 (or MD5) hash of a FILE. It is the underlying structure and byte sequence of the actual binary (or hexadecimal) data that BitTorrent clients understand and use and the hashsum in the metadata is the signature of an individual 1,2,4 or 8 MB PIECE of that binary data. Also each piece MAY contain the binary data of ONE, or MORE FILEs and a file may be split across SEVERAL PIECES. <<< read that bit <<< carefully, because that is where your idea falls apart totally with respect to BitTorrent.