> BitTorrent makes the process of where to put files far more > cumbersome than should be necessary, though. There's really no reason to > create "torrents" apart from plain old files. All you need is a hash of the > file and a service for looking up duplicates. This is again an issue of > protocol layering.
You need a secure hash of each individual chunk of the file that you intend to download as a unit from a given source (hashes over smaller regions that combine to have the same effect naturally work just as well). This is effectively all a .torrent is. Why? Because computers suck and that will -never- change. Most have non-ECC RAM and many still use parallel ATA hard drives. Both of which are prone to passing undetected bit errors in data on. On top of that crappy consumer network equipment can corrupt data even further. These are why if you run bittorrent you'll see it receiving pieces of the file that fail the hash check and redownloading them from somewhere else. A distributed download protocol that does not do integrity checking at or near the transferred chunk size is doomed to failure. If you only have the overall file hash how do you determine which part of the thing you received from 50,000 peers is bad? rsync ain't gonna cut it. -greg _______________________________________________ p2p-hackers mailing list [email protected] http://lists.zooko.com/mailman/listinfo/p2p-hackers
