Torrent file information

Miscellaneous

Displays all information contained inside a .torrent file.

Display

A .torrent file:

Max size of the input data is 10 MiB. ▲ clear By file upload: ▼ clear From URL (http[s], ftp[s]): ▼ clear By direct input: (UTF-8) Enter one or more wrappers (comma-separated): If necessary, enter initial data here: (UTF-8) Wrappers are executed in sequence on shared data string. For example, to supply base64-encoded stream of GZIP-compressed data enter wrappers: base64, gzip and fill the data input with the base64 stream. ¶ If data is not entered information from other tabs (upload, by URL and direct) is used to replace data on this page. This lets you enter gzip as a wrapper here and upload a file using upload tab while leaving data on this page empty. ¶ Currently supported wrappers are: base64, bzip, cslashes, datauri, direct, ftp, ftps, gzip, hex2bin, http, https, qprintable, upload, url, urlencoding, zlib. ¶ Upload By URL Direct input Custom Ctrl+Shift+E

This tool uses freely available PHP functions to parse .torrent files (which format is known as bencoding) from this page. ¶

Updated 20 Oct 2011: fixed issue with single-file torrents and torrents containing large files (> 2 GiB). ¶

Torrent file format ¶

A torrent file contains semi-text, semi-binary data in so-called Bencoding format. Each item can be an integer, a string, an onordered list and a dictionary with key/value pairs (ordered by keys). Each item starts with a single letter except for strings (i, l, d for integers, lists and dictionaries correspondingly) and ends with letter «e». ¶

Integers

are encoded in torrent files as i52e (number 52);

Strings

are stored as 10:bittorrent (length + colon + the string itself) in torrent files;

Lists

are simply recursively encoded values so it's like li123e4:worde that represents 2 items: a number 123 and a string «word»;

Dicrionaries

are similar to lists except they start with letter d and have a bencoded string before each value. Both lists and dictionaries can be nested; dictionaries must be sorted by keys.

Torrent structure ¶

Given above info torrent files are dictionaries (hashes) of the following values: ¶

info

A dictionary with torrent contents (files and hashes);

announce

URL of the primary tracker;

announce-list

Is optional; if present defines a list of alternative announce URLs (bittorrent trackers);

creation date

Optional field with a timestamp;

comment

Optional, a string;

created by

Optional credits of the program used to create this .torrent file (such as uTorrent, BitComet or Azureus);

encoding

Optional encoding algorithm used to generate pieces of the info dictionary.

The info dictionary can be of two forms: ¶

• for single-file torrents it contains 3 information fields: name, length and optional md5sum;
• for multiple-file torrents it has name (base directory for contained files) and files fields, the latter being a list of files that this torrent contains. Each files entry has 3 items: length (file size), optional md5sum and path (relative to info/name).

You can parse the contents of torrent files via the torrent creator – owever, if you just want to check inside a torrent file it's more convenient to use the torrent file info form above. You can upload a torrent or enter its URL to parse and view its contents, details and information. ¶

Infohash algorithm ¶

A torrent infohash is a 40-character SHA-1 checksum of the bencoded info dictionary. In PHP you can get it as: ¶

echo sha1(bencode($torrent['info']));

Or, if you're using the BEncoded PHP class you only need this: ¶

$torrent = new BEncoded(file_get_contents('my.torrent'));
echo $torrent->InfoHash();

You might also be interested in our online hash generator that is able to calculate SHA-1, MD5, CRC32 and other checksums. ¶

Reference pages ¶

• BitTorrent Protocol Specification – includes .torrent structure, bencoding format (name of format .torrent complies to), protocol conventions, algorithms and other related information.
• Torrent File Format of BitComet client.
• BitTorrent protocol – Wikipedia's article on the concept of BitTorrent itself; see also Peer-to-peer file sharing.
• Comparison of BitTorrent clients on Wikipedia.