Psiphon
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| Psiphon | |
| Developer: | Citizen Lab |
|---|---|
| Latest release: | 1.5 / February 9, 2007 |
| OS: | Cross-platform |
| Use: | Censorship circumvention |
| License: | GNU General Public License |
| Website: | psiphon.civisec.org |
Psiphon is a software project designed by University of Toronto's Citizen Lab under the direction of Professor Ronald Deibert, Director of the Citizen Lab[1]. Psiphon is a circumvention technology that works through social networks of trust and is designed to help Internet users bypass content-filtering systems setup by governments, such as China, North Korea, Iran, Myanmar, Saudi Arabia, United Arab Emirates, United States, Vietnam, Pakistan and others.
"We're aiming at giving people access to sites like Wikipedia," a free, user-maintained online encyclopedia, and other information and news sources, Michael Hull, psiphon's lead engineer, told CBC News Online.[2]
Contents |
[edit] History and Functionality
Psiphon is an internet proxy, described as "... a censorship circumvention solution that allows users to access blocked sites in countries where the Internet is censored." The psiphon sofware "...turns a regular home computer into a personal, encrypted server capable of retrieving and displaying web pages anywhere." [3] Psiphon was originally implemented in Python, but has been re-designed and re-written in C++, and designed as a cross-platform (Windows and Linux versions are currently available), user friendly proxy server tool which uses a https protocol to transfer data. With a user name and password, people in countries that use Internet content filtering can send encrypted requests for information to a trusted computer located in another country and receive encrypted information in return. As https protocol is widely used for secure communication over the Internet (from web mail to Internet banking), no government can block https traffic without further restricting its citizens' ability to use the web, something that has not dissuaded these governments' Internet censorship efforts thus far.
According to Nart Villeneuve, Director of Technical Research from the Citizen Lab, "The idea is to get them to install this on their computer, and then deliver the location of that circumventor, to people in filtered countries by the means they know to be the most secure. What we're trying to build is a network of trust among people who know each other, rather than a large tech network that people can just tap into."[4]
Psiphon takes a substantially different approach to censorship circumvention than other tools used for such purposes, such as The Onion Router aka Tor. Psiphon requires no download on the client side, and thus offers ease-of-use for the end user. But unlike Tor, psiphon is not an anonymizer, as the server logs all of the clients surfing history. Psiphon differs from previous approaches in that the users themselves have access to server software which is easily installed on the Microsoft Windows platform. The ease which users themselves are able to set up their own servers should, given a certain level of use of the sofware, result in a greater number of servers being online. A great number of servers online would make the task of attacking the overall user base more difficult for those hostile to use of the psiphon proxy than attacking a few centralized servers, because each individual web proxy would have to be disabled one by one.
In the most recent edition of the software, the psiphonode pings the Citizen Lab to “check in” and returns your public IP, which is then distributed to users. Although this does create the theoretical danger of a canonical list of psiphonodes which could be a target for an adversary determined to block psiphon, the Citizen Lab does not archive this information as a matter of policy. Additionally, users have the option to configure their psiphonodes not to "check in" with the Citizen Lab.
Through the psiphon control panel, psiphonode administrators have access to a log of sites that their psiphonites access, and the above underscores the importance that a psiphonode administrator and psiphonite have a level of trust that each will act responsibly when using psiphon[opinion needs balancing]. Please see "Theoretical Problems" below for an alternative view on whether psiphonode administrator access to a log of sites is a security risk.
The software is funded by the Open Society Institute and was released under the GNU General Public License (GPL) on 1 December 2006. The Psiphon development team is actively exploring ways to sustain the project, possibly through a "professional service" that would complement and help fund the free, open source version.
[edit] Theoretical Problems
As mentioned above, he latest version of this software has a "call home" option, which is active by default, so that each user upon signing on can choose to report to check their IP. The list of IPs could theoretically fall into the wrong hands if any of these events happen, a) the computer on which the list is stored is hacked b) the legal authorities in the country which keeps the list demands the list, using criminal or other penalties as a "stick" c) the person(s) in charge of the computer make an innocent mistake and accidently post the list on the internet d) the owners of the list commercialize the product and a vendee accidently is made privy to the list e) the owners of the list/computer the list is on decide they don't care anymore. Also of concern is the feature "Through the psiphon control panel, psiphonode administrators have access to a log of sites that their psiphonites access", this is not a feature but an extreme security risk because psiphone can be used as a "honeynet" to ensnare users. However, doing so would be in contravention of the explicit model upon which psiphon rests, which is social networks of trust. An IEEE Internet Computing article[5] discusses in part the security risks inherent in P2P approaches such as psiphon, with specific mention of the danger presented by logging by the services themselves.
A repressive government could establish psiphone sites as a way of catching dissedents, but only a person tricked into trusting the wrong psiphonode administrator (which would be a misuse of the social networks of trust, the model upon which psiphon rests), a foolish person, or an insufficiently educated person not following, or not understanding, the user guide, or not properly understanding how the "network of trust" psiphon model works could fall victim to such a ruse. Moreover, the method currenlty used by most people to get around Internet censorship -- open public proxies -- is a much more effective and simple way for a "repressive government" to set up a honey pot albeit less targeted to specific suspected or known dissedents.
[edit] Psiphon and data retention
The United Kingdom and some other European countries have data retention policies. Under these policies Internet Service Providers are obliged to retain a record of all their clients web browsing. The data retention period varies from six months to three years. In the UK this retained data is available to a very wide range of public bodies, including the police and security services. Anyone who operates a psiphonode in one of these countries needs to be aware that a record is kept of all web browsing through their computers. On the 15th March 2006 the European Union adopted Directive 2006/24/EC which requires all member states to introduce statutory data retention. The United States of America does not have a statutory data retention regime, though such a provision is under discussion. Such records as are retained by Internet Service Providers or web sites may be obtained by Federal authorities, without judicial oversight, using a National Security Letter.
[edit] References
- ^ Psiphon Official Homepage
- ^ "Tool to circumvent internet censorship set to launch", CBC News Online, 2006-12-01.
- ^ Frequently Asked Quesions
- ^ Boyd, Clark. "Bypassing China's net firewall", BBC News, 2004-03-10. Retrieved on March 28, 2007.
- ^ Clarke, Ian; Scott G. Miller, Theodore W. Hong, Oskar Sandberg, Brandon Wiley (January/February 2002). "Protecting Free Expression Online with Freenet". IEEE Internet Computing 6 (1): 40-49.
[edit] See also
- Hacktivism
- The Six/Four System
- GNUnet
- Internet censorship
- Freedom of information
- OpenNet Initiative
- Ronald Deibert
[edit] News
- CBC The Hour - December 4, 2006
- BBC: Web censorship 'bypass' unveiled
- Canada.com: Canadian software touted as answer to Internet censorship abroad
- CNN: Experts find path around Internet firewalls
- Computerworld: Liberation software designed on basis of trust
- Globe and Mail: Scaling the walls of Web censorship
- Reuters: Canada experts find path round Internet firewalls
- CNN International: psiphon interview with Dr. Ron Deibert
