fbleyvacar Posted June 19, 2012 Share Posted June 19, 2012 Is it possible that two different seeders that are seeding the same file and provide all other metadata in the torrent file in the same exact manner will produce, by definition, the same info_hash for the torrent. In this hypothetical everything is the same. The file name, the size of the pieces, the same everything. Just two different people on two different computers, perhaps in two different parts of the world? Link to comment Share on other sites More sharing options...
cassie Posted June 20, 2012 Share Posted June 20, 2012 Unless I'm not reading your post correctly (yes, it's very late, where I am), that is exactly how bittorrenting works. Everyone that is part of the swarm is sharing the exact same content (including the info_hash)... if this was not so, none of the pieces would get past the hash-checks and the task(s) would never complete. Geographical location of each peer's computer is not relevant to the completion of any specific task. Link to comment Share on other sites More sharing options...
kluelos Posted June 20, 2012 Share Posted June 20, 2012 I suspect you didn't ask the question you meant to ask, somewhere in there. Instead of two seeders, I suspect you meant two torrent-creators. This is not a new idea or question in the field, about which guys do doctoral dissertations. The bittorrent info-hash calculation includes the date and time, down to the second, at which the torrent was created. While it is theoretically possible that two files could have the same hash value (known as a "hash collision"), cryptographic hash functions are designed so that the probability of this event is a practical impossibility – even if an expert is intentionally looking to find two files with the same hash value. In other words, you are much more likely to be probed by aliens than to find a hash collision between two torrents. Link to comment Share on other sites More sharing options...
Vasy Posted June 22, 2012 Share Posted June 22, 2012 A workaround (tested to work by me) is to make the torrents with different piece sizes and so the hashes will be different and the client will recognize them as two different torrents. Although this will not be possible if the torrents are already made by others with the same piece size. And if you're asking if a seeder from a torrent will help those from the other torrent, it's theoretically possible by LTSeeding (BitComet proprietary protocol) but only on public torrents. LTSeeding is done file by file, no matter where it comes from, as long as both are public torrents and the peers use BitComet with LTSeeding enabled. Link to comment Share on other sites More sharing options...
kluelos Posted June 22, 2012 Share Posted June 22, 2012 If you research bittorrent info-hash creation, you'll discover that the infohash is created from the .torrent file -- and does not include data from the contents other than indirectly. (Yeah, this took me by surprise too.) The date and time of creation are included in the info-hash calculation, as are the tracker names and ports. But wait, you think ... I did. Then I thought again. Yes, that information CAN be changed. But what about .... Exactly. When is the hash of the .torrent. ever checked? Never. When I went back and looked, I realized that I had never been told any different. I had just been guilty of making faulty assumptions. Link to comment Share on other sites More sharing options...
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