PortableTor is a free repackaged version of the bundled Tor Software by Roger Dingledine and Nick Mathewson. The program allows the end user to connect to the Tor anonymity network from a removable media without installing anything to the hard drive.
A convenient package for anonymous web browsing. PortableTor allows you to connect into the Tor anonymous internet system from any computer with your flash or thumb drive. This allows you to browse the internet anonymously from public locations, such as internet hotspots, library, or school computers and public terminals.
PortableTor has all of the features as the regular Tor, except without actually installing the application. You could also use PortableTor if you just don't like installing programs on your computer, and you'd rather have a standalone program with all of its dependant files in one location.

Portable Tor is based on the principle of Onion Routing and was implemented with some modifications:

1. The user installs a client on his computer, called the Onion Proxy. This program connects to the Tor network. During the initial phase you download the program, a list of all existing and usable Tor. Start with a digital signature provided list is kept by directory servers that are delivered their public key with the gate-source code, to ensure that the onion proxy receives an authentic list.

2. If the list is received, the onion proxy chooses a random route through Tor servers.

3. The client with the first Tor server negotiate an encrypted connection. If this is built, it will be expanded to a new server. One each Tor server always knows its predecessor and his successor. Tor thus relies on a combination of just three servers in order to reach the largest possible anonymity in yet more acceptable latency. The success depends on the fact that at least one server is trusted, an attacker does not even monitor the start and end point of communication.

4. Once a connection has been established to be about the data sent. The last occurs while the server as an endpoint of communication. He is also known as exit nodes, or nodes (engl. exit node).

The license of this software is Free, you can free download and free use this web browser software.