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What are torrents and how do they work?

Torrents are an extremely popular method of sharing files. Also known as peer-to-peer (P2P) file-sharing, torrents often get a bad reputation despite being an easy way to share files. There is a lot of misinformation online about torrenting, and this article hopes to clarify what torrents are and how to use them without breaking any laws.

Torrents: a brief history

Bram Cohen, a computer programmer and college student, invented and developed the BitTorrent protocol in 2001. It was the first P2P file-sharing protocol, which he revealed at a computer science conference in 2002. His idea was to create a system that breaks large files into smaller pieces to facilitate more efficient sharing between peers. P2P file sharing is often attacked by entertainment industries (such as music and movie studios) as it allows an easy way of sharing their copyrighted materials. Many countries have outright blocked torrenting, and many laws have been passed related to the issue. Many popular torrenting websites such as “The Pirate Bay” and “KickassTorrents” have been blocked or taken down.

How does torrenting work?

Normally, when a user tries to download a file (large or small) from a website or a server, there are only two participants in the process: the recipient (downloader) and the server that contains the file. This means that if any of the two sides are disconnected, they need to start the download again from the beginning. Additionally, both parties’ internet speed (and other factors) are important in determining how fast the file is downloaded. In other words, the file is being sent from one computer (or server) to another – in one direction.

When downloading a file through a torrent, there are more than just two computers involved in the process. To help illustrate how torrenting works, one must imagine a large network of people constantly sharing information amongst each other. Files on a P2P network broken down into pieces to make the downloading process faster. Every user that downloads a file is constantly uploading parts of it to the network simultaneously. This means information is being sent back and forth in two directions.

In this way, when you download a file from a torrent client, you are downloading pieces of it from multiple users, and the BitTorrent protocol pieces it together to make a whole file. This makes downloading both faster and more efficient. Additionally, torrenting often allows users to reach a faster download speed as the speed is not reliant on just one or two servers but a whole network of servers.

Are torrents illegal?

Despite the controversy that surrounds torrent usage, there are many legal uses for the torrent protocol. The legality of torrenting depends on the nature of files being shared. Governments, large corporations, archivers, game publishers, and individuals use torrents to share and distribute their files legally in a fast and efficient manner. For example, the popular archiving website Archive.org provides a torrent version of every file uploaded to the website. As long as it is legal to share and distribute the files being torrented (that is, no copyright infringement laws are being broken), using torrents is completely legal.

Terms commonly associated with torrenting

Because it was a new technology, P2P file sharing developed terms to describe different things related to the protocol. Therefore, before you begin using torrents, it is important to understand the related vocabulary and jargon. These are terms which anyone interested in torrenting should be familiar with:

BitTorrent

This is the protocol that programs use to distribute and share large files on a P2P file-sharing network. This is the code that is used to break down files and rebuild them. It changes file sharing on a network to become two-directional.

Torrent Client

Also known as a BitTorrent client, this is the program that users access to implement the BitTorrent protocol. In other words, this is the application or software that connects users with torrent files to download and creates a network between people who all download the same file. There are many torrent clients nowadays, with slight differences between them, but they all follow the same general principle of implementing the torrent protocol.

Peers, Seeders, and Leechers

All users that are currently uploading or downloading a file on a P2P network are known as peers. When the file is downloaded, some users keep uploading fragments of the file after their download is complete to allow others to download it – these are known as seeders. On the other hand, leechers are people who only download the files (from multiple peers) on a P2P server but do not allow their bandwidth to be used for uploading the file. When their download is complete, instead of seeding the torrent by uploading its files, they stop the upload process. To sum up: peers download and upload, seeders upload the file after it has been downloaded, whereas leechers only download the file and don’t upload any parts.

Swarm

All the users who upload or download a file on a torrent client are known as a swarm. In other words, the peers, seeders, and leechers that have parts of a torrent file or the entire file in the download or upload phase.

Torrent File

This refers to files that are being shared on a torrenting network. This can also mean the file containing the metadata of shared files, such as details of the pieces it must be broken down into (known as checksums) and the address of trackers.

This is a special type of hyperlink that contains information related to a torrent file. The torrent client uses this information to find trackers and a swarm for the torrent file linked to the magnet link. Because it is a hyperlink, it can easily be shared between users. Pasting a magnet link into a browser address bar prompts you to launch your BitTorrent client and download the file associated with that particular magnet link.

Tracker

For every swarm, there exists a server that does not participate in the downloading or uploading within the network but instead keeps track of everything going on. This includes (but isn’t limited to) seeds, peers, and which users own which checksums. Trackers do not have a copy of the torrent file. Trackers and torrent clients are continuously exchanging information about torrent files and users in a swarm.

Advantages of using torrents

Now that you know what torrents are and how they work, you might be wondering what the pros of using them are as opposed to more traditional methods of downloading.

Faster download speeds

A huge advantage of using torrent clients is the increased download speeds. Regardless of your internet speed or the server you are downloading from, download speeds from a BitTorrent client will almost always outpace the speed of downloading from traditional methods. This is because it allows you to reach almost the limit of your device’s internet speed. Because there is no central computer (server) to download from, the uploading capacity of all users in a swarm (except for leechers) impacts the speed with which you can download a file. This means that slow connections can still download large files within a reasonable time frame. The more popular a file is, the more seeders and peers will be available, thus allowing you to maximize your download speed. BitTorrent clients also usually have options to increase the bandwidth you are using for the download. This means that popular files are likely to be downloaded faster.

Disconnect, pause, and resume your download whenever needed

Another important advantage of using peer-to-peer networks to download files is that you do not need to stay connected to the internet for the entire time of downloading. If a user is disconnected from the swarm at any point (for any reason whatsoever), the torrent client still stores information about which checksums (parts) of the torrent file have already been downloaded. When the connection is restarted, the torrent client will reconnect with available peers and seeds to download the remaining pieces of the file to be downloaded.

Easy to find

There are hundreds (if not thousands) of online databases and repositories where you can find millions of torrents, many of them illegal to download, such as music, games, movies, books, shows, and so on. For online pirates, torrents and torrent websites are a great way to download this content.

Cannot be taken down easily

Each torrent file is technically stored on the device of every user that downloaded the torrent (and is either a peer or a seeder). As the torrent is not stored in one place, it is close to impossible for copyright enforcement agencies to “takedown” torrents – they would have to go to each individual device and delete the torrent, which is not practical or possible. Therefore, torrents are a great way to avoid copyrighted files getting taken down (as opposed to traditional download methods, where deleting the file from the original server would no longer make it downloadable or accessible).

Disadvantages and potential risks of using torrents

While torrents are convenient and easier to use than most people think, they do come with some considerable drawbacks which you must consider.

No seeders, no downloads

We’ve already mentioned how popular files have a larger swarm (people downloading and uploading the files), which means they are more likely to be downloaded faster. This is because there will concurrently be more seeders and peers simultaneously, all of which are continuously uploading parts of the file for others to download. The flipside of the argument is that unpopular files will not have enough seeders or peers for others to download the file. Instead, it will mostly have leechers (people who have already downloaded the file then turn off seeding, therefore not re-uploading any parts of the file). Without enough seeders available, users cannot download torrent files, and they stay stagnant. Many torrent files have died in this way – there are no seeders left to upload the file, so users are stuck waiting to download.

No file previews

Another problem that users face when downloading files from a torrent client is that there is usually no way to preview a file. This means that they must trust that the file matches its name and the attached metadata. Unfortunately, inexperienced users can end up downloading an entirely different file (including malware) from a bad source.

Users with limited bandwidth

In some countries, internet service providers limit the bandwidth of their users for both downloads and uploads. Because peers both download and upload data for every file they are downloading, this can quickly use up their limited bandwidth. If you subscribe to a plan from your internet service provider that gives you access to unlimited bandwidth, this is not an issue to be concerned with.

Users with limited internet speed

For users who don’t have a high internet connection speed, downloads using torrent clients can significantly slow down the internet for other tasks. This throttling can make it difficult to perform simply internet tasks, such as opening up web pages. This is because downloading a torrent both downloads and uploads the file. As a result, many users often resorted to only downloading from torrent clients in the night as they sleep.

Risks of downloading malware

It is relatively easy to add malware to folders and files shared over a torrent network. Users with malicious intent can use BitTorrent protocol to hide their malicious software within popular files to distribute their malware to a large network of people. Some torrent clients offer anti-malware scanning to avoid this problem, which is why it is important to select a good torrent client. Additionally, major sources used to get torrents adhere to rigorous standards to prevent infected torrents from being listed on their website or database.

Many people debate the legality and ethics of using peer-to-peer file-sharing networks. First, it is important to remember that the BitTorrent protocol itself is not illegal, but many people use it for illegal means. This is similar to the legality of guns, where owning a gun is not illegal, but using it to rob a store is obviously against the law. For torrenting, the programs and protocols are not illegal in most countries, including the United States, United Kingdom, Australia, and Canada. However, using the program for copyright infringement is against the law and can have legal consequences, including heavy fines.

Users who are caught torrenting usually only receive “warnings” from their internet service providers (ISPs). Many people do not concern themselves with the legality of using torrents, as there are rarely any legal actions taken against users who have downloaded a torrent. Therefore, torrenting networks are notorious for being used for online piracy. Additionally, many users use VPNs to remain anonymous while torrenting and feel more safe accessing pirated content.

Security and Privacy Concerns

The IP addresses of all users in a swarm are exposed to the torrent client (and potentially, other users in the swarm). This poses a potential security and privacy risk that users should be aware of. The only solution for this problem is to use VPN when accessing a torrent network.

How to use torrents to download files safely

Now that you know the pros and cons of using torrents, you’re probably wondering the best way of using BitTorrent clients. Do not be discouraged by the security disadvantages of these clients; there are simple steps you can take to download torrents safely and easily. Most torrent clients work similarly, and despite seeming difficult, are relatively easy to use.

How to find the torrent files you’re looking for

Torrent clients often come with a search function, which can be used to locate the file you want to download by looking through the metadata of millions of torrent files. After searching, you will usually be presented with a list of files related to your search query, with details on the number of seeders and peers. You should always try to select files with a higher number of seeders and peers, and a high seed:peer ratio is preferable. This will guarantee you can download the file as fast as possible. For example, if there are 500 seeders, the torrent client has access to 500 full copies of the file to download from. This is inherently better than having only 10 seeders (10 full copies) or having 1 seeder and 20 peers (only one full copy and 20 partial copies).

You can also access a torrent file by finding a magnet link from many torrent-sharing websites available online. A simple search query with the file name and “torrent” will usually yield dozens of results for websites that have magnet links. However, please be aware that there are many “fake” torrent files that are infected with malware – this is why we recommend using only trusted sources for finding torrents. You can also share magnet links with your friend via email or any other online communication method to download specific torrent files.

After selecting the file you want to download, the torrent client will usually handle the rest. In your torrent client, you can set a limit on the bandwidth allocated for seeding, or if you prefer to be a leecher, you can block seeding altogether. Some BitTorrent clients also allow users to limit the number of simultaneous downloads to keep their internet speed from being throttled or limit the bandwidth allocated to the client.

Use a VPN!

One of the best ways to protect your privacy online is to use a VPN service. A VPN (Virtual Private Network) is the best way to hide your IP address from other users in a swarm, the torrent client, and even your internet service provider. This works by diverting all your internet traffic through a proxy server, effectively masking your IP address, and keeping your data and location secure. Always connect to a VPN server (preferably to a country where P2P file sharing is not penalized) before starting your torrent client. We recommend using an open-source VPN such as OpenVPN. However, we must warn you that using a VPN will not protect you from malware; for that, you should download anti-malware software.

Our favorite torrent clients

These torrent clients have been selected for their safety, popularity, features, and low learning curve. They will help you access torrent networks safely and securely.

  • BitTorrent – this is an open-source option that is easy to use and yet has most of the features you need when torrenting
  • uTorrent –  one of the most used torrent clients, is it user-friendly and packed with many features (although it does have annoying display ads)
  • Vuze – we recommend this option for heavy torrent users that have many files. The program has an excellent organizer built-in to keep your downloads arranged according to your preference.
  • Transmission – this is the best option for macOS users

Hopefully, this article has clarified what torrenting is, its advantages and disadvantages, an overview of how it works, and ways to find and download torrents while staying safe and legal.

Peter is completing his final year of computer engineering at the University of Texas at Austin. He spends his free time on GitHub, gaming, or browsing the internet for obscure and interesting websites. He is a big proponent of open-source software and has contributed to projects such as OBS Studio.

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