2. CONTENTS Introduction Working Terminology Features Drawbacks
Countermeasures
3. INTRODUCTION What are Torrents ? torrent (/trnt/) In the
BitTorrent file distribution system, a torrent file is a computer
file that contains metadata about files and folders to be
distributed, and usually also a list of the network locations of
trackers, which are computers that help participants in the system
find each other and form efficient distribution groups called
swarms. A torrent file does not contain the contentto be
distributed; it only contains information about those files, such
as their names, sizes, folder structure, and cryptographic hash
values for verifying file integrity. Depending on context,a torrent
may be the torrent file or the referenced content.
4. STRUCTURE OF A TORRENT FILE
5. A torrent file is a specially formatted binary file. It
always contains a list of files, integrity metadata about all the
pieces, and an optional list of trackers. A torrent file is a
bencoded dictionary with the following keys: Announce : The URL of
the tracker Info : this maps to a dictionary whose keys are
dependenton whether one or more files are being shared: Name :
suggested file/directory name where the file(s) is/are to be saved
Piece length : number of bytes per piece. This is commonly 28KiB =
256 KiB = 262,144 B. Pieces : a hash list. That is, a concatenation
of each piece's SHA-1 hash. As SHA-1 returns a 160-bit hash, pieces
will be a string whose length is a multiple of 160-bits Length :
size of the file in bytes (only when one file is being shared)
Files : a list of dictionaries each corresponding to a file (only
when multiple files are being shared). Each dictionary has the
following keys: Path : a list of strings corresponding to
subdirectory names, thelastof which is the actual file name Length:
sizeof the file in bytes. All strings must be UTF-8 encoded.
6. SAMPLE DE-BENCODED TORRENT FILE Here is what a de-bencoded
torrent file (with piece length 256 KiB = 262144 bytes) for a file
debian- 503-amd64-CD-1.iso (whose size is 647 MiB = 678301696
bytes) might look like:
7. WORKING
8. HOW IT WORKS !?! When we uploada torrent on a trackers site,
Its tracks the transfers of the files happeningbetween the
uploaderand the persons who downloadthe torrents from that site.
The connectionsare announcedto all the peers and TCP connectionsare
setup. A seeder to leecher ratio is maintainedand feedbacks are
stored for further downloads.
9. TERMINOLOGY Client : The program that enablesp2p file
sharing via the BitTorrent protocol.Examples of clients include
Torrent and Vuze.
10. Fake : A fake torrentis a torrent that does not containwhat
is specified in its name or description (e.g. a torrent is said to
contain a video, but it containsonly a snapshot of a moment in the
video, or in some cases a virus). Health : Health is shown in a bar
or in % usually next to the torrentsname and size, on the site
where .torrent is hosted. It shows if the pieces of the torrentare
available to download (i.e. 50% means that only half of the torrent
is available). A torrent with higher number of seeds will be
healthier.
11. Index : An index is a list of .torrent files (usually
includingdescriptionsand other information) managed by a website
and availablefor searches. An index website can also be a tracker.
Leech : Leech has two meanings. Often, leecher is synonymouswith
downloader(see above): simply describinga peer or any client that
does not have 100% of the data. The term also refersto a peer (or
peers) that has a negative effect on the swarmby having a very poor
share ratio, downloadingmuch more than they upload. Leeches may be
on asymmetric internet connections or do not leave their BitTorrent
client open to seed the file after their download has
completed.However, some leeches intentionallyavoid uploadingby
using modified clients or excessively limiting their upload
speed.
12. Peer : A peer is one instanceof a BitTorrent client running
on a computer on the Internet to which other clientsconnect and
transfer data. Usually a peer does not have the complete file, but
only parts of it. However, in the colloquialdefinition,"peer" can
be used to refer to any participantin the swarm (in this case, it's
synonymouswith "client"). Piece : This refers to the torrented
files being dividedup into equalspecific sized pieces (e.g. 64kB,
128kB, 512KB, 1MB, 2MB or 4MB). The pieces are distributedin a
random fashionamong peers in order to optimize trading
efficiency.
13. Seed : A Seed refers to a peer possessing 100% of the data.
When a leech obtains100% of the data,that peer by definitionbecomes
a Seed. Seedingsolenmly refers to leavinga peer's connection
availablefor other peers, i.e. leeches, to downloadfrom. Normally,
a peer should seed more data than leech. However, whether to seed
or not, or how much to seed, is dependent on the availabilityof
leeches and the choice of the peer at the seeding end.
14. Tracker : A tracker is a server that keeps track of which
seeds and peers are in the swarm. Clientsreport information to the
tracker periodicallyand in exchange, receive information about
other clientsto which they can connect. The tracker is not directly
involvedin the datatransfer and does not have a copy of the
file.
15. FROM WHERE TO GET TORRENTS
16. FEATURES Full Selectivity : There is full selectivity of
files. We can choose the files which we need and ignore the junk
files from a torrent.
17. LOGGING OF EVENTS
18. FULL MONITORING
19. STATISTICS
20. BANDWIDTH MANAGEMENT
21. CHAT ENVIRONMENT
22. MORE FACTS AND FEATURES Torrents with high seeds to peer
ratioscan achieve up to 30MB/s of downloadingspeeds which is not
frequently possible for a single server. Torrents work at no profit
no loss. Not even a single person is benefittedat all by sharing
torrents. Basicallyits a free service and wealth is only
generatedby advertisements. Torrents work on P2P connectionsand
thus are not dependent of any particularclient or server.
Bit-Torrent networks use maximum bandwidthand they have increased
internet usage 20 to 30 % data annually.
23. PROBLEMS AND DRAWBACKS Piracy is the major drawback of
torrents. Torrents include billionsof piratedsoftware.
Distributionof copyright contentis very easy on Torrent directories
and are a big threat to Companies and firms.
24. MISGUIDING ADVERTISEMENTS Advertisements sometimes confuse
a user and once clicked, One has to pay for that mistake. Those
scripts run Maliciousand Infected Programs on the machine and force
the user to download junky material.
25. CRACKS AND KEYGENS
26. PIRACY AND CYBER LAWS All these cracks are a means of
piracy on the internet. Using crack softwares is a crime in many
countries and the penalty dependsupon the nationsCyber Law.
According to Section 63 of the Act 1994 of Indian Cyber Law, there
is a minimum jail term of 6 months for copyright infringement. The
section also provides for fines up to Rs. 2,00,000 and jail term up
to three years or both. Any person or company who indulges in
unauthorizedcopying, sale, downloadingor loading of software is
punishableunder this section. Distributionof pirated softwares is
also a punishableoffence. All such people are committing offences
under Section 66 of Information TechnologyAct, 2000 and are
therefore punishableunder Section 66 of the Information Technology
Act
27. VULNERABILITIES AND KEYHOLES Torrents works on specific
ports, So a hacker can step into our machine by those ports by
following methods : He can intrude as a seeder of a torrent which
contain a Trojan Through chat rooms of torrent clients, He can get
valuable information Cracked and Pirated softwares frequently
containa virus thus infected users can be used as bots.
Downloadedfiles may not containthe files mentionedin the
description So fake torrents are a waste of time and money as
well.
28. SECURITY AND COUNTERMEASURES Never trust any crack or
keygen Ensure the reputationof the file Check the links before
clicking Downloadtorrents from verified and trusted sites only Use
original Softwares, So prefer buying them Be aware in the social
chat groups
29. THANK YOU
30. Harshvardhan Malpani B.Tech 2nd year student
MaharajaAgrasen Institute of Technology Affiliatedto GGSIPU August
2013 Summer Training(Cyber Security, i3indya)
