Yes with the access to the index i agree, but i was assuming the other party would not have access to that.
(But of course, if its over torrent and public the other party would have access to this data..)
But lets not forget, it would only reach the data over torrent if its not local, and as it would do it only once for each block, someone that would be spying over torrent would not have access to further queries after the first hit over that particular piece.
Also, as far as i know, you would only know about the pieces, if its asking it from you, so you would need to seed from as many peers as you can, to have access to all the pieces requests from the party you are interested in..
So even assuming a sophisticated party that could reverse engineer over piece offset access, (and let not forget that if the block size is big, this gets even harder), still, i don't think it would be possible to rebuild the query.
