The Hydra Project

A Distributed, private BitTorrent tracker framework with goals of:

... user privacy, anonymity, survivability & distributed ratio maintainability.

Goals of THP:

• Maintain user privacy & anonymity (as much as possible for a private BitTorrent tracker)
• Survivability of the overall network in the face of a single or several (not 100%) of the network being attacked or raided
• Distributed ratio and user management across multiple trusted domains (a bit like OpenID, for private trackers)
• Development of the "spec" Hydra Project protocol (implemented in Ruby on Rails) which can be ported over to PHP, etc.

Anonymity and privacy precautions:

• User IP addresses are never stored on disk or the database
• Email addresses are never collected
• Password hashes are stored in the database with a random salt for each password hash (to curb the feasibility of widespread rainbow attacks)
• Uploaded .torrent files are not associated with users
• User information of who seeded/uploaded particular torrents is never stored
• User share ratio information is, however, kept (bytes downloaded/uploaded)
• One requirement of private trackers is to lookup IP Addresses to correlate username (last login from IP) with torrent client IPs
• For this problem we use memcached, which only ever stores the IPs in system RAM: http://www.danga.com/memcached/
• Web server configuration is up to the user; it is highly advised to disable IP and/or request logging altogether.

Survivability:

• Multiple private THP domain owner/operators ("admins") grant trust rights to fellow private tracker operators, which both must use the THP sync protocol
• At anytime, a server admin can remove a tracker from its list of trusted THP trackers (i.e. in the event of a raid or server compromise)
• User accounts (including password hash information) are shared across all trusted domains and are synced periodically; thus allowing users to login to any known site in the network
• Share ratio information (bytes upped/downloaded) is shared across all trusted servers; note: which files were downed/upped are never stored for obvious privacy reasons.
• Torrents are shared across servers. TBD: exactly how this works, including data synchronization and category push/pull mechanics, etc.
• .torrent files are modified to include a list of all (or a specified subset) of the tracker announce URLs for the trusted trackers. Thus if a single tracker goes down, the .torrent file should still be valid if at least one of its announce URLs is still operational. (Experimental)
• TBD: how to propagate bans or other user management actions across trusted trackers.

Open protocol:

• See the HydraProjectSyncAPI for more details on the intra-server REST-based API
• Feedback is welcomed and encouraged from the community

Credits:

• Bram Cohen for BitTorrent itself: http://bitconjurer.org/
• The TorrentStrike PHP private tracker, based on torrentbits & bytemonsoon code: http://sourceforge.net/projects/torrentstrike
• William Morgan's Ruby BitTorrent library: http://rubytorrent.rubyforge.org/