# Tor Browser

## Summary


Tor Browser is a standalone desktop application that helps users browse the web safely and anonymously. Since many users use the Internet via a web browser, Tor Browser is a useful application for anonymity. It hides your device's IP address and its location. It prevents third parties from snooping into your online activities or even tracking you. 

Tor Browser is based on the open sourced code of Firefox browser. It adds further privacy and security settings. 

Underneath, Tor Browser relies on the Tor network of relay nodes. In the past, it was difficult to use Tor since one had to install a number of tools separately. Today, Tor Browser bundles all the necessary tools into a single archive of files, thus making it easier for users to adopt Tor.

## Discussion

### What are the features of the Tor Browser?

Tor Browser is cross-platform and available for x86 and x86\_64 architectures. Encryption and decryption are done automatically. It can update itself to latest version. What previously required separate installations of Tor, Firefox browser, Torbutton (Firefox add-on) and Polipo (HTTP proxy), are now conveniently bundled within the Tor Browser. 

A new separate circuit is automatically created for each domain though they share a common guard node. This process is transparent to users but Tor Browser allows users to inspect the current circuit and request a new circuit if so desired. From within the browser, users can also request Tor bridges by solving a captcha. Each circuit lives for only ten minutes. 

Since each website is isolated from another, this prevents tracking from third parties. Tor Browser resists browser fingerprinting. To prevent cookie-based tracking, cookies and browsing history are cleared when the browser is closed. It also prefers DuckDuckGo over Google as the search engine, since Google tracks you and logs your search queries. 


### What are the variants of Tor Browser for different platforms?

Tor Browser is available for Microsoft Windows, Apple MacOS and GNU/Linux. As of March 2019, an experimental version 8.5a8 is also available for Android. 

Two popular add-ons that come with Tor Browser by default are NoScript and HTTPS Everywhere. 

For Android, there's also **Orbot**, a proxy that enables Tor access for any mobile app. **Orfox** is a browser for Android that was developed as part of the Guardian Project. This is likely to be discontinued when a stable version of Tor Browser for Android is released. 

Third-party **Onion Browser** is the one to use for iOS. 


### I already use private/incognito mode in Firefox/Chrome. Why do I need Tor Browser?

Private modes avoid saving your browsing history and cookies. Otherwise, they are vulnerable to fingerprinting and network adversaries. Shortcomings are plugins, fingerprinting, DNS leaks, SSL state leaks, autofill and site-specific zoom. This is where Tor Browser becomes useful. 

On a related note, Tor provides anonymity at the routing layer. However, Tor can't protect you if your hardware is compromised, such as a key logger. Tor doesn't encrypt traffic between the exit node and final destination, for which you should use app-level encryption, such as SSL for HTTPS traffic. In fact, an add-on such as *HTTPS Everywhere* can help in enforcing security for sites that support it. Electronic Frontier Foundation has a nice animation to show how HTTPS works alongside Tor.

Tor will also not protect you from improper usage. For example, BitTorrent over Tor is not anonymous. 


### What are some alternatives to the Tor Browser for anonymous web browsing?

Tor Browser is not the only way to achieve anonymity while browsing the web. *I2P* provides a peer-to-peer distributed communications layer. It's suited for hidden services. *Freenet* uses a similar P2P technology. Linux-based distributions that focus on privacy and anonymity (some of which use Tor underneath) include *Tails*, *Subgraph* and *Freepto*. 

*Qubes OS* is a desktop OS focused on security. It uses virtualization to give users any OS of their choice. *Whonix* OS is integrated into Qubes. With Whonix, we can connect to Tor from inside a VM. 

*Epic Browser* doesn't use any special networking architecture. However, it disables history, third-party cookies, DNS pre-fetching, and autofill in forms. These are common ways in which privacy can be compromised. 

*Brave* browser integrates Tor. Users can open a private tab with Tor. 

Other alternatives are listed at alternative.me.

## Milestones

Oct  
2003

Tor network is deployed. Tor code is open sourced under MIT license. Tor itself is an improvement over Onion Routing that started as a research project in 1995. 

Mar  
2008

Version 1.0.0 of Tor Browser Bundle is released. 

Jun  
2017

Tor Browser 7.0 is released with multiprocess mode and content sandbox as two major features. Sandboxing is not yet available on Windows. Until this release, lack of sandboxing was a problem and was exploited by the FBI. This version is based on Firefox 52 Extended Support Release (ESR). ESR is meant to help organizations to mass deploy the browser.

Sep  
2018

Tor Browser version 8 is released based on Firefox Quantum codebase that came out in November 2017. User interface is Photon UI that Firefox Quantum uses. Also in September, alpha release of **Tor Browser for Android** happens.

May  
2019

Tor Browser version 8.5 becomes the first stable release for Android. Tor Browser also gets newly designed logos compatible with Firefox's Photon UI.