What is P2P?

Three people with laptops around a table
(Image credit: Unsplash / Brooke Cagle)

P2P, or “Peer to Peer”, is an alternate way of building networks that eschews the traditional “client and server” network architecture in favor of a decentralized network architecture. 

In a P2P network, each peer connects directly to other peers to share and access resources within the network. Peers take on the role of both client and server, eliminating the need for a central server. 

People often use this type of network to share files, so I’ll go into a little bit more depth about why that works, why it’s a good idea, and what precautions you should take while using P2P.

Why use P2P?


P2P services have a bad reputation which is, in my opinion, undeserved. You’ve almost certainly heard of the most infamous ones, such as BitTorrent, Bitcoin, and the Tor network.  These P2P technologies disproportionately pop up in the news because they can facilitate cyber-crime, but the reality is that most P2P technology is used for relatively benign purposes. Also, it’s way cheaper than running servers. 

P2P networks don't rely on a central server. Each peer can share and access resources directly with others. This eliminates the single point of failure and increases the network's resilience. If one peer goes offline, the network continues to function seamlessly.

Since P2P networks distribute the load among all peers, there's no need for expensive central servers or large-scale infrastructure. This reduces costs for service providers, but that’s not all.

P2P networks scale naturally as more peers join. Each new peer brings additional resources, such as bandwidth and storage, which enhances the network's overall capacity and performance. This scalability is particularly useful for applications that need to handle large volumes of data or a high number of transactions.

In addition to being tough to bring down, P2P networks are fast. By leveraging the combined bandwidth and processing power of all peers, P2P networks can offer faster download and upload speeds. This is especially beneficial for file-sharing applications where users need to transfer large files quickly and efficiently.

Most people think about file sharing when they hear about P2P, and for good reason. One of the earliest P2P file-sharing services, Napster, completely revolutionized the way people shared music with each other in the early 2000s.

This paved the way for the BitTorrent protocol, a widely used P2P protocol still employed to this day for distributing large files. BitTorrent breaks files into small chunks and distributes them among all users on the network, who then share these chunks with others, making the download process faster and more efficient.

However, there are many other popular uses for P2P technology than just file-sharing. Originally built on P2P technology, Skype enables subscribers to make voice and video calls directly with each other without routing data through a central server.

P2P also powers practically every cryptocurrency network we use today. For example, Bitcoin uses a P2P network to facilitate secure and decentralized transactions. The public ledger powered by P2P technology ensures that Bitcoin remains transparent, trustworthy, and immutable.

Finally, if you ever owned a PS3, you may remember the Folding@home project. This program used P2P networks to harness the processing power of thousands of volunteer computers for scientific endeavors. By contributing fractions of their processing power, Folding@home users powered a program that models protein folding and misfolding, which is related to diseases such as Alzheimer's. 

P2P drawbacks

While the decentralized nature of peer-to-peer networks offers numerous benefits, there’s also some inherent drawbacks that come with having no central authority.

One of the most significant risks associated with P2P networks is malware distribution. Because files are shared directly between peers, there’s often no mechanism in place to identify whether a file is legitimate or bundled with malware. Malicious actors can easily exploit P2P networks to distribute harmful software with the help of unwitting users of the network, leading to a much wider proliferation than through well-regulated software download venues such as mobile app stores.

Most P2P platforms also expose your IP address in order to function, meaning that anyone you’re connected to can see which ISP you’re using, as well as your general location. A skilled hacker may be able to leverage on that information with other pieces of knowledge to commit identity fraud, or may take the direct route of hacking you through your IP if you have an exposed web service.

P2P networks also often consume a lot of bandwidth, as users share data with multiple peers simultaneously. This can lead to slower internet speeds and increased data usage, which might be problematic for users with limited bandwidth or data caps.

Using cloud storage solutions instead, such as Google Drive and Dropbox, allows you to take advantage of the ease of P2P file sharing while taking the bandwidth toll off of your network. These services provide a suite of security features designed to protect your data, including encryption, authentication, and regular patches to protect against web attacks.

Virtual Private Networks also offer secure alternatives for data sharing within a controlled environment. VPNs like NordVPN offer the ability to create secure P2P networks powered entirely by encrypted VPN connections, allowing you to create your own file-sharing service between your own devices that’s completely invisible to outside observers. There’s also the added bonus of keeping your IP address secret while you’re using a P2P network, which I’ll address more below.

Staying safe on P2P networks

Using peer-to-peer networks can be risky, but with a few extra steps you can get the most out of using a P2P network without putting your device in harm's way. 

First off, you should make sure you choose a reputable P2P client for file-sharing. This is especially true if you’re choosing between BitTorrent clients. I recommend Transmission, which is regularly updated to patch security vulnerabilities and improve functionality. It’s also open source, so you know exactly what the software is doing on your system. By using a P2P client that’s actively maintained and trusted by the community, you’re reducing the chances of using a piece of software that could introduce malware onto your system.

You should also be aware that using a P2P client exposes your IP address to other users on the internet. There’s a few things you can do about this, but the most important one is to install a firewall. It acts as a barrier between your computer and the internet, monitoring incoming and outgoing traffic to block hacking attempts on your device. 

That solves the issue of being attacked, but your home IP address is still visible when you use a P2P client which can reveal your location to others. The best VPNs will hide your IP address when you’re using a P2P client, making it impossible for other users on the network to know where you’re really connecting from. 

You should make sure you’re using one with a reliable kill switch, as this is essential for ensuring your home IP isn’t exposed if your connection to the VPN drops out. Best of all, using a VPN encrypts your traffic, making it impossible for your ISP to spy on your Bitcoin transactions or file-sharing.

P2P in review

P2P is extremely useful for building resilient networks that can effectively deal with censorship, hacking attacks, and natural disasters while retaining functionality. Just look at the Bitcoin network. 

Unfortunately, they’re also an easy way for hackers to profile you by scanning your IP address and learning more about your network. They’re also usually bandwidth and memory-hungry, depending on the type of P2P network you’re participating in. 

There’s not much you can do about the latter, but using a strong VPN can effectively mask your IP address, protecting you from hackers and ISPs spying on what you do on a P2P network.


Why is P2P illegal?

The short answer is that P2P technology itself isn't illegal. Peer-to-peer networks are a legitimate and powerful method for sharing resources and data directly between users without relying on a central server. 

However, the legality issues arise from how P2P networks are used, specifically when it comes to sharing copyrighted material without authorization.

How risky is using P2P?

Using P2P networks can be risky due to potential malware, unauthorized access, data integrity issues, privacy concerns, and legal problems. However, by taking specific security precautions, you can significantly reduce these risks. 

Use a reputable torrent client, install a firewall, and utilize a VPN with a reliable kill switch to protect your data and privacy. 

Can you get scammed using P2P?

Yes, you can get scammed using P2P networks. The decentralized nature of peer-to-peer technology means that there is no central authority overseeing transactions, which can make it easier for fraudulent activities to occur. 

Scammers can exploit this by distributing malware-infected files, sharing corrupted data, or engaging in financial fraud. To protect yourself, always take steps to verify the identity of anyone you interact with on a P2P network. 

Olivia Powell
Commissioning Editor for Tech Software

Olivia joined TechRadar in October 2023 as part of the core Future Tech Software team, and is the Commissioning Editor for Tech Software. With a background in cybersecurity, Olivia stays up-to-date with all things cyber and creates content across sites including TechRadar Pro, TechRadar, Tom’s Guide, iMore, Windows Central, PC Gamer and Games Radar. She is particularly interested in threat intelligence, detection and response, data security, fraud prevention and the ever-evolving threat landscape.

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