To: Cyber Fromf San Diego
Re: 295B-SD-67338, O3/29/2005

of which clients are online sharing which files. Trackers do not store or relay the files themselves, but instead introduce clients to one another to make file sharing by individuals easier. A client communicates with a tracker to ask it for the Internet Protocol (IP) addresses of clients sharing the file that the client wishes to download. The client then automatically communicates directly with those other clients to download the desired file from them.

The BitTorrent system enables users to download many types of files, including movies, music, and software, which are called "content" files. In order to download a content file with BitTorrent, a user must first find and download an associated "torrent" file. Torrent files contain the information BitTorrent clients need to download associated content files. Namely, a torrent file includes the address of a tracker, the name of a content file, the size of the content file, the size of the parts into which the file is divided, and unique file identifiers for each part. Torrent files are small files that essentially tell one computer where and how to get a content file directly from another computer.

The key philosophy of BitTorrent is that users should upload (transmit outbound) at the same time they are downloading (receiving inbound.) In this manner, network bandwidth is utilized as efficiently as possible. BitTorrent is designed to work better as the number of people interested in a certain file increases, in contrast to other file transfer protocols. To date, it is the fasted way to download music and movies, illegally, on the Internet.

This is a joint investigation with the San Diego Computer and Technology Crime High-Tech (CATCH) Response Team, and the US Department of Immigration and Customs Enforcement (ICE). Local Agents from ICE will be contacting the recipients of this EC to assist in the preparation and execution of the
search warrants. If it is determined that the subject of the lead is not in the Division being notified, an EC will be generated to inform the affected Division.

A draft affidavit is being prepared and will be forwarded electronically to the separate divisions in preparation for the coordinated search warrants. Separate from the affidavit, an excel spread sheet listing subject information and the initial target information packet provided by the MPAA will be forwarded to the lead Agent. Closer to the time of the search warrant, questions to ask the subject during the interview will be prepared and provided to each Division. It is anticipated that numerous computer systems or large storage configurations

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