View source for BitComet

{{Short description|BitTorrent, FTP and HTTP client}}
{{Infobox software
| name = BitComet
| logo = BitComet logo.svg
| screenshot = BitComet screenshot.png
| caption = BitComet client version 1.40 running on Windows 10
| developer = BitComet Development Group (China)<ref name="BDGP">{{cite web|url=http://investing.businessweek.com/research/stocks/private/snapshot.asp?privcapId=62194735|title=BitComet Development Group Private Company Information|work=[[Bloomberg Businessweek]]|access-date=14 April 2014|archive-date=13 December 2019|archive-url=https://web.archive.org/web/20191213120837/http://investing.businessweek.com/research/stocks/private/snapshot.asp?privcapId=62194735|url-status=dead}}</ref>
| released = {{Start date and age|2003|08|06}}
| ver layout = stacked
| latest release version = {{Multiple releases
 |branch1  = Windows
 |version1 = {{wikidata|property|preferred|references|edit|Q753524|P348|P400=Q1406|P548=Q2804309}}
 |date1    = {{Start date and age|{{wikidata|qualifier|preferred|single|Q753524|P348|P400=Q1406|P548=Q2804309|P577}}}}
 |branch2  = macOS
 |version2 = {{wikidata|property|preferred|references|edit|Q753524|P348|P400=Q14116|P548=Q2804309}}
 |date2    = {{Start date and age|{{wikidata|qualifier|preferred|single|Q753524|P348|P400=Q14116|P548=Q2804309|P577}}}}
}}
| operating system = [[Windows 2000]] and later, [[Android (operating system)|Android]],<ref>{{cite web|url=https://play.google.com/store/apps/details?id=com.bitcomet.android|title=BitComet|website=Google Play Store|access-date=2020-12-10|archive-date=2021-10-31|archive-url=https://web.archive.org/web/20211031231755/https://play.google.com/store/apps/details?id=com.bitcomet.android|url-status=live}}</ref> [[macOS]]
| programming language = [[C++]]{{Citation needed|date=January 2017}}
| language count = 52
| language footnote = <ref>{{Cite web|url=http://wiki.bitcomet.com/Help_Translations_of_BitComet|title=Help_translations_of_bitcomet &#91;BitComet Wiki&#93;|access-date=2010-02-26|archive-date=2010-03-05|archive-url=https://web.archive.org/web/20100305185630/http://wiki.bitcomet.com/Help_Translations_of_BitComet|url-status=live}}</ref>
| genre = [[BitTorrent client]]
| license = [[Adware]]
}}
'''BitComet''' (originally named '''SimpleBT client''' from versions 0.11 to 0.37) is a cross-protocol [[BitTorrent]], [[Hypertext Transfer Protocol|HTTP]] and [[File Transfer Protocol|FTP]] [[client (computing)|client]] written in [[C++]] for [[Microsoft Windows]] and available in 52 different languages.<ref>{{cite web|title=Supported Languages in BitComet|date=2009-03-11|url=http://www.bitcomet.com/|access-date=2008-05-13|archive-date=2015-12-11|archive-url=https://web.archive.org/web/20151211134049/http://www.bitcomet.com/|url-status=live}}</ref> Its first public release was version 0.28. The current BitComet logo has been used since version 0.50.<ref>{{cite web|title=BitComet BitTorrent Client|date=2006-05-10|url=http://www.quartermeg.com/bitcomet-review.htm|access-date=2008-05-13|archive-url=https://web.archive.org/web/20080513203435/http://www.quartermeg.com/bitcomet-review.htm|archive-date=2008-05-13|url-status=dead}}</ref>

== Features ==
The BitComet program is a multi-threaded multi-protocol hybrid [[download manager]] and [[BitTorrent (protocol)|BitTorrent]] [[peer-to-peer]] (P2P) file-sharing application. It supports simultaneous download tasks. To complete a particular download, it can draw parts of files from many sources across different P2P and [[client–server]] protocols.

BitComet's main features include an embedded [[Internet Explorer]] window to let users search for torrents. Along with the features typical of contemporary BitTorrent clients, it supports [[UPnP]] gateway configuration, bandwidth scheduling, [[BitTorrent (protocol)#Web seeding|Webseeding]], selecting only certain files for download inside a torrent package, [[NAT traversal]] (''removed in v.1.03''),<ref name="what is bitcomet">{{cite web
  | title = What is NAT Traversal in BitComet??
  | date = 2009-11-24
  | url = http://wiki.bitcomet.com/Understanding_BitComet#What_is_NAT_Traversal_in_BitComet.3F
  | access-date = 2010-02-23
  | archive-date = 2019-08-18
  | archive-url = https://web.archive.org/web/20190818123222/http://wiki.bitcomet.com/understanding_bitcomet#What_is_NAT_Traversal_in_BitComet.3F
  | url-status = live
  }}</ref> [[Peer exchange|Peer Exchange]] (''in older versions, using a proprietary protocol and starting with v.1.19 also by using the Extension Protocol, implementing a PEX mechanism compatible with μTorrent / Mainline PEX''),<ref name="PEX in BitComet">{{cite web
  | title = PEX in BitComet.
  | date = 2010-02-21
  | url = http://www.bitcomet.com/doc/changelog.htm
  | access-date = 2010-02-23
  | archive-date = 2010-12-17
  | archive-url = https://web.archive.org/web/20101217053502/http://www.bitcomet.com/doc/changelog.htm
  | url-status = live
  }}</ref> Initial-Seeding ([[Super seeding|Super-Seeding]]) and support for [[Magnet URI scheme|Magnet Links]].

When downloading, BitComet provides the option to prioritize the first and last portions of media files so that files may be previewed before they are completely downloaded.<br />It also has a "Preview Download Mode" in which all pieces of the torrent will be, basically, downloaded sequentially thus allowing the user to play a media file while downloading (provided that the downloading speed and piece availability stay ahead of playing bitrate).<br />BitComet also allows users to share their .torrent files, on a searchable P2P network, with other BitComet users through the torrent sharing feature, named "Torrent Share" in previous versions and renamed to "Torrent Exchange" since v.1.17.<ref>{{cite web
  | title = Torrent Share and Torrent Exchange
  | date = 2010-01-01
  | url = http://wiki.bitcomet.com/Torrent_Exchange
  | access-date = 2010-01-01
  | archive-date = 2013-10-05
  | archive-url = https://web.archive.org/web/20131005065144/http://wiki.bitcomet.com/Torrent_Exchange
  | url-status = live
  }}</ref> BitComet uses the [[Kademlia]] (mainline) [[Distributed hash table|DHT]] to operate even when the [[BitTorrent tracker|tracker]] is offline. BitComet is capable of downloading files over HTTP and FTP as well as bittorrent, and it includes download plugins for [[Firefox]], Internet Explorer, and [[Maxthon]].<ref name="what is bitcomet" />

An optional plugin is available to connect to the [[eDonkey network|eD2K]] network. The plugin is a modified version of the [[GPL]] [[eMule]] program. When installed, it connects automatically to a server.<ref>{{cite web
  | title = eMule Plugin for BitComet
  | date = 2008-03-27
  | url = http://www.bitcomet.com/doc/plugin-emule.htm
  | access-date = 2008-05-13
  | archive-date = 2008-05-13
  | archive-url = https://web.archive.org/web/20080513233148/http://www.bitcomet.com/doc/plugin-emule.htm
  | url-status = live
  }}</ref>

[[File:Bitcomet FLV Player.JPG|thumb|BitComet FLV Player version 1.3|200px]]
The software includes an application to play [[Flash Video]] files ([[.flv]] and [[.swf]] files).<ref>{{cite web
  | title = BitComet FLV Player (Flash Video Player)
  | date = 2008-03-27
  | url = http://www.bitcomet.com/tools/flvplayer/index.htm
  | access-date = 2008-05-13
  | archive-date = 2008-05-13
  | archive-url = https://web.archive.org/web/20080513233203/http://www.bitcomet.com/tools/flvplayer/index.htm
  | url-status = live
  }}</ref>

In February 2011, BitComet launched an anonymous downloading feature to its VIP customers. Using this feature, downloads will be handled by BitComet VIP servers and the real IP address of the user will be hidden.<ref>{{Cite news|url=https://torrentfreak.com/bitcomet-anonymous-downloads-110602/|title=BitComet Adds Support for "Anonymous" Downloads – TorrentFreak|date=2011-06-02|work=TorrentFreak|access-date=2018-04-05|language=en-US|archive-date=2018-04-05|archive-url=https://web.archive.org/web/20180405214928/https://torrentfreak.com/bitcomet-anonymous-downloads-110602/|url-status=live}}</ref>

=== Optional standalone software ===
BitComet.com offers a [[BitTorrent tracker]] available for download from the official site.<ref>{{cite web
  | title = BitComet Tracker
  | date = 2008-03-27
  | url = http://www.bitcomet.com/tools/tracker/index.htm
  | access-date = 2008-05-13
  | archive-date = 2008-04-30
  | archive-url = https://web.archive.org/web/20080430051206/http://www.bitcomet.com/tools/tracker/index.htm
  | url-status = live
  }}</ref> The FLV player program can also be downloaded separately and used independently of the BitComet software.

==== Search engine ====
The search site is google.atcomet.com

== Controversy and criticism ==
=== Hash reporting ===
Since version 0.86 BitComet includes discussion and stat-tracking features which send information about torrents to the Bitcomet.com servers, including the torrent [[Hash function|hash]].{{citation needed|date=February 2023}}

=== DHT exploit ===
During version 0.60, BitComet received bad publicity because its implementation of the [[Distributed hash table|DHT]] feature, which was new at the time, could be exploited to ignore the private flag of a tracker. This allowed users to avoid download and upload ratio restrictions, which are common on private trackers. Some private trackers responded to this by [[blacklist]]ing version 0.60.<ref name="slyck BitComet Banned">{{Cite web
| url=http://www.slyck.com/story1021.html
| title=BitComet Banned
| access-date=2007-01-15
| year=2005
| author=Thomas Mennecke
| archive-url=https://web.archive.org/web/20070124131627/http://www.slyck.com/story1021.html
| archive-date=2007-01-24
| url-status=dead
}}</ref> BitComet developer RnySmile reverted the client back to version 0.59 in response to the blacklisting.<ref name="slyck BitComet Reverts to Version .59">{{Cite web
| url=http://www.slyck.com/story1030.html
| title=BitComet Reverts to Version .59
| access-date=2007-01-15
| year=2005
| author=Thomas Mennecke
| archive-url=https://web.archive.org/web/20070124132253/http://www.slyck.com/story1030.html
| archive-date=2007-01-24
| url-status=dead
}}</ref>

The [[Distributed hash table|DHT]] exploit was fixed in version 0.61.<ref name="slyck BitComet 0.62 and You">{{Cite web
| url=http://www.slyck.com/story1094.html
| title=BitComet .62 and You
| access-date=2006-12-03
| year=2006
| author=Thomas Mennecke
| archive-url=https://web.archive.org/web/20070518105128/http://www.slyck.com/story1094.html
| archive-date=2007-05-18
| url-status=dead
}}</ref><ref name="slyck BitComet 0.64 Released">{{Cite web
| url=http://www.slyck.com/story1152.html
| title=BitComet .64 Released
| access-date=2006-01-15
| year=2006
| author=Thomas Mennecke
| archive-url=https://web.archive.org/web/20071008092503/http://www.slyck.com/story1152.html
| archive-date=2007-10-08
| url-status=dead
}}</ref>

=== Padding files ===
Starting with version 0.85 (from early 2007), BitComet added a non-standard option to its torrent maker that ensures that no two data files in a multi-file torrent occupy the same BitTorrent "piece." To accomplish this, BitComet includes in the torrent a collection of empty "padding" files which houses the remainder of each file's last "piece". While these files are transparent to BitComet users, they damage the performance of other clients, because peers must devote resources and bandwidth to the padding files, with no benefit to the non-BitComet users. These files can constitute up to 10% of the total data transferred, creating a substantial drain on the swarm.<ref name="TorrentFreak">{{Cite web
| url=http://torrentfreak.com/bitcomet-pollutes-bittorrent-with-junk-data/
| title=BitComet Pollutes BitTorrent with Junk Data
| date=2007-08-23
| author=Ernesto
| publisher=TorrentFreak
| access-date=August 24, 2007
| archive-date=2007-08-24
| archive-url=https://web.archive.org/web/20070824150123/http://torrentfreak.com/bitcomet-pollutes-bittorrent-with-junk-data/
| url-status=live
}}</ref> BitComet developers added this feature to allow support of a feature called Long-Term Seeding in which the BitComet client can download files from other BitComet clients who have an identical file but not from the same torrent.  It also allows the downloading of individual files from other non torrent sources like ED2K links. The addition of the padding file ensures that a complete version of the file can be obtained rather than being unable to complete the relevant file or last "piece"  <ref name="Bitcoment Wiki">{{Cite web
| url=http://wiki.bitcomet.com/align_file_to_piece_boundary
| title=align_file_to_piece_boundary [BitComet Wiki]
| access-date=May 13, 2015
| archive-date=May 12, 2015
| archive-url=https://web.archive.org/web/20150512043305/http://wiki.bitcomet.com/Align_File_to_Piece_Boundary
| url-status=live
}}</ref>

Creation of padding files has been enabled by default since version 0.85, and as of version 1.36 is still enabled by default.{{citation needed|date=May 2008}}

=== FileHippo controversy ===
{{confusing|section|reason=the relationship/relevance of AppHit.com to either party in this 'controversy'|date=December 2023}}
The download site [[FileHippo]] ceased carrying new versions of BitComet in April 2008, with this announcement.

<blockquote>
As of April 2008 FileHippo will no longer be updating BitComet. As they have copied the FileHippo site text, files, images and update checker and are passing it off as original work. We recommend you use a different more reputable torrent client such as uTorrent.<ref>{{cite web |url=http://www.filehippo.com/download_bitcomet/ |title=Download BitComet 0.99 – FileHippo.com |date=April 2008 |access-date=2009-12-18 |archive-url=https://web.archive.org/web/20080420170253/http://www.filehippo.com:80/download_bitcomet/ |archive-date= 2008-04-20}}</ref>
</blockquote>

This occurred after FileHippo reportedly noticed that the design and code of the AppHit.com site was very similar with the one FileHippo used, copying not only icons, but text from FileHippo's website and FileHippo's own original update checking software.

Because AppHit and BitComet were contractual partners, FileHippo decided to stop carrying BitComet.  BitComet has since terminated the partnership; by 2015 FileHippo made BitComet available once more.

=== Torrent file format ===
According to the official BitTorrent specification, 'All strings in a .torrent file that contains text must be [[UTF-8]] encoded'.<ref name="BitTorrentSpec">{{Cite web
| url=http://www.bittorrent.org/beps/bep_0003.html
| title=The BitTorrent Protocol Specification
| author=Bram Cohen
| access-date=2009-08-26
| archive-date=2014-02-08
| archive-url=https://web.archive.org/web/20140208002821/http://bittorrent.org/beps/bep_0003.html
| url-status=live
}}</ref> When generating torrents on non-Latin character systems such as Chinese or Japanese, BitComet versions prior to 1.20<ref name="BitComet release notes">{{Cite web
| url=http://www.bitcomet.com/doc/changelog.htm
| title=BitComet release notes
| author=BitComet
| access-date=2010-03-27
| quote=Core Improve: use UTF-8 encoding when making torrent file by default for all language versions of Windows.
| archive-date=2010-12-17
| archive-url=https://web.archive.org/web/20101217053502/http://www.bitcomet.com/doc/changelog.htm
| url-status=live
}}</ref> encoded the files' names and paths using the Windows Chinese/Japanese code page, and stored a UTF-8 version in a non-standard attribute.<ref name="BitCometSpec">{{Cite web
| url=http://blog.bitcomet.com/bitcomet/post_413/
| title=BitComet – Torrent File Format
| author=BitComet Support Team
| access-date=2009-08-26
| quote=In BitComet v0.58 or before, the string is encoded using MSCB (user's code page), and a ".utf-8" key is added for UTF-8 encoded string. In v0.59, the default encoding is changed to UTF-8 if the user's code page is neither Chinese nor Japanese.
| archive-url=https://web.archive.org/web/20090514092326/http://blog.bitcomet.com/bitcomet/post_413
| archive-date=2009-05-14
| url-status=dead
}}</ref> Starting with the March 2010 release of version 1.20, BitComet's torrent format now conforms to the standard.

== See also ==
* [[Comparison of BitTorrent clients]]
* [[BitLord]] (based on BitComet)

== References ==
{{reflist|30em}}

== External links ==
* {{official website}}

{{BitTorrent}}

[[Category:BitTorrent clients]]
[[Category:C++ software]]
[[Category:Windows-only freeware]]
[[Category:2003 software]]