What Is Tor?
Tor (The Onion Router) is a decentralized network designed to enable anonymous communication over the internet. Originally based on technology developed at the U.S. Naval Research Laboratory, it is now maintained by The Tor Project, a nonprofit organization.
The name "Tor" derives from "Onion Routing." Communication data is wrapped in multiple layers of encryption - like the layers of an onion - and relayed through several servers, making it extremely difficult to link the source and destination of a communication.
How the Tor Network Works
Traffic on the Tor network passes through three relays in sequence.
1. Guard Node (Entry Node)
The first relay your device connects to. It knows your IP address but cannot determine your final destination. For security reasons, the guard node remains fixed for a certain period.
2. Middle Node
A relay that bridges the guard node and the exit node. It only knows the IP addresses of the nodes immediately before and after it - neither the origin nor the destination of the communication.
3. Exit Node
The relay that serves as the gateway from the Tor network to the regular internet. It communicates with the destination website but cannot identify the original sender. The IP address visible to the website is that of the exit node.
Communication between each relay is individually encrypted, ensuring that no single relay can see the full picture. This is the essence of "onion routing."
Features of the Tor Browser
The Tor Browser is built on Firefox and comes with built-in Tor network connectivity.
Anonymity Assurance
- All traffic is routed through the Tor network
- Cookies, history, and cache are automatically deleted when the browser is closed
- NoScript is built in to restrict JavaScript execution
Fingerprint Countermeasures
- All Tor Browser users share an identical User-Agent string
- Window size is standardized to prevent identification by screen resolution
- Canvas, WebGL, and AudioContext fingerprinting are blocked
- Font enumeration is restricted
These measures make tracking via browser fingerprinting significantly more difficult.
Advantages of the Tor Browser
Strong Anonymity
With three relay hops and multi-layer encryption, Tor provides a level of anonymity that surpasses VPNs. Simultaneously identifying both the source and destination of a communication is extremely difficult. For those who want to learn more about the principles behind online anonymity, books on internet privacy offer valuable background.
Censorship Circumvention
In countries and regions where internet censorship is enforced, Tor serves as a means to access blocked websites. It is an indispensable tool for journalists and human rights activists.
Free to Use
The Tor Browser is completely free and open source. There are no monthly fees like those charged by VPN services.
Fingerprint Resistance
Because all users share the same browser configuration, individual identification through fingerprinting is extremely difficult.
Disadvantages of the Tor Browser
Reduced Speed
Routing through three relays significantly slows down browsing compared to a normal connection. It is not well suited for video streaming or large file downloads.
Blocked by Some Sites
Since Tor exit node IP addresses are publicly known, some websites and services block access from Tor. CAPTCHA prompts also tend to appear more frequently.
Exit Node Risks
Traffic between the exit node and the destination is not encrypted unless the site uses HTTPS. A malicious exit node operator could potentially intercept unencrypted traffic, so it is important to only visit HTTPS-enabled sites.
Limits of Complete Anonymity
Even when using Tor, your identity is revealed on services where you are logged in. Additionally, traffic from applications other than the Tor Browser does not pass through the Tor network.
Tips for Using Tor Safely
- Do not enter personal information in the Tor Browser. Avoid logging in with your real name
- Do not resize the browser window - doing so disables fingerprint protections
- Do not install additional extensions - they may compromise your anonymity
- Always keep the Tor Browser updated to the latest version
- Only visit HTTPS-enabled sites
- Do not open files downloaded via the Tor Browser outside of Tor
VPN vs. Tor
Both VPNs and Tor are effective for privacy protection, but their characteristics differ.
- Speed: VPNs are significantly faster
- Anonymity: Tor offers stronger anonymity - VPN providers may retain logs
- Ease of use: VPNs are more convenient and protect all application traffic
- Cost: Tor is free; most VPN services require a subscription
- Use case: VPNs for everyday privacy; Tor when strong anonymity is required
For more on VPNs, see our VPN guide. For a comparison of VPN encryption methods, our VPN protocols guide is also helpful. If your only goal is to hide your IP address, a proxy server is another option, though it falls far short of Tor and VPNs in terms of encryption and anonymity. You can also check your IP address and fingerprint score while using the Tor Browser on the IP Check-san homepage.
Tor Developments in 2024-2025
The Tor Project continues to drive technical innovation. Here are the key developments in 2024-2025.
Arti: Reimplementing the Tor Client in Rust
The Tor Project is advancing the "Arti" project, a reimplementation of the traditional C-based Tor client in Rust. Improved memory safety and a modernized codebase are expected to deliver significant gains in security and maintainability. Developers interested in the architecture of anonymity networks may find a guide to network anonymity insightful.
Evolving Censorship Circumvention
To counter sophisticated censorship in countries like China and Russia, Tor's connection technologies (Pluggable Transports) continue to evolve. New bridge technologies such as Snowflake and WebTunnel enable connections even in regions where Tor access is blocked.
Onion Service Improvements
The performance and reliability of Onion Services (formerly Hidden Services), served via .onion domains, have improved. The widespread adoption of Onion Services v3 has brought stronger encryption and enhanced security through longer addresses (56 characters).
Defenses Against Traffic Analysis Attacks
Research into defenses against advanced traffic analysis attacks (timing attacks and fingerprinting attacks) is progressing. Efforts to introduce padding and dummy traffic aim to make it harder to de-anonymize users based on communication patterns.
Practical Guide to Using the Tor Browser
Here are concrete steps for safely setting up and using the Tor Browser.
Installation Steps
- Download only from the official Tor Project website (torproject.org). Never download from unofficial sources
- Verify the signature of the downloaded file to ensure it has not been tampered with
- After installation, select "Connect" on first launch. In censored regions, configure a bridge under "Tor Network Settings"
- Once connected, visit the IP Check-san homepage to confirm your IP address has changed to a Tor exit node's address
Anonymity Maintenance Checklist
- Set the Tor Browser's security level to "Safer" or "Safest"
- Do not resize the browser window (fingerprint protection)
- Do not install additional extensions
- Do not enter personal information in the Tor Browser
- Do not open files downloaded via Tor outside of Tor
- Only visit HTTPS-enabled sites
Combining Tor with a VPN
Tor over VPN (connecting to a VPN before using Tor) can hide your Tor usage from your ISP. However, be aware that the VPN provider may log your Tor usage. If combining the two, choose a trustworthy no-log VPN service.