Weiterempfehlen Leserbrief
31.07.2008

Internationaler Netzwelt.de-Leitfaden: Werkzeuge gegen die China-Firewall

China-Kracher: So lässt sich die Olympia-Zensur umgehen

Sicherheit

German IT online magazine netzwelt.de combats press censorship

China-Cracker: Netzwelt.de IT Guide to Circumvent Olympic Games Censorship

As the Olympic Games approach, the Chinese Empire continues to do what it has practiced for more than 200 years—they batten down the hatches. Which means in the digital age: internet cool down, disagreeable web pages are being made unavailable. Journalists from countries such as the United States, the United Kingdom, France, or Germany are outraged, and so are politicians. Free media coverage and research are not possible under such circumstances.

However, the situation on the internet is reminiscent of the Trojan War: the choice of the right ways and means may lead to victory. In order for freedom of press and information still to succeed, netzwelt.de - with its 1.2 million unique users the leading German IT online magazine—has compiled an IT guide in four languages (English, German, French, Spanish). Addressing journalists already in China as well as those who are scheduled to leave for Olympic Games media coverage, the guide shows how to circumvent internet censorship in China.

In doing so, the netzwelt.de guide offers much more than the general recommendations for reporting from dictator states, as for instance made by the organization "Reporters without Borders." The anti-censorship tutorial "China-Cracker: Netzwelt.de IT Guide to Circumvent Olympic Games Censorship" may be downloaded from www.netzwelt.de/news/78257.

The Status Quo

In China, the state has been controlling the internet for the last ten years. In 1998, the Chinese security ministries initiated the Golden Shield Project, which in effect is one of the largest internet firewalls worldwide. According to expert estimations, several thousand censors are working to make sure that more than 200 million surfing Chinese primarily see those pages the government wants them to see. In doing so, they make extensive IT provisions:

1. Static solution: Disagreeable web pages are being blacklisted according to their IP addresses. A Firewall blocks these pages for every computer within China. An IP address is an identification number for a computer on the internet.

2. Filter solution: State censors install filters on the central Chinese servers. Those filters foreclose unwanted internet addresses (URLs) including keywords that are on the index, such as "blog," "feed" (news tickers on pages), "Tibet," or "press freedom."

3. Furthermore, China practices the so-called DNS poisoning: Normally, a special server takes care that one can reconstruct the IP address, i.e. a computer's identification number, from the name of the website one accesses. For example, in order for www.google.de to be translated into the IP 209.85.129.147, the Domain Name System is necessary, which is situated on servers as a database. "If China changes the allocation, the translation of the domain is literally being poisoned", netzwelt.de expert Moritz Zielenkewitz explains.

Gate to the Chinese Empire

But like the stone wall, the Chinese firewall is not insurmountable. The world of IT offers excellent tools for accessing blocked web pages even from China—be it as a journalist or as a regular tourist. And this is how it works:

China-Cracker 1—Cracking the Firewall with the Help of Software in China:

The silver bullet to crack Chinese internet censorship surely is the so-called TOR computer network. In order to enter this network, one needs to download the free TOR Software from netzwelt.de (www.netzwelt.de/software/4188). Every computer with installed TOR software serves as a nodal point within the TOR network. Thousands of computers worldwide act as relays for incoming and outgoing internet information. The task of the TOR network in this case is to outsmart the censorship attempts. It works like this: The person trying to call up a specific web page does not contact that very page directly. Instead, the TOR network randomly reroutes the request via the nodal points consisting of other computers worldwide. This is like a game of ping pong. If the last nodal point then connects with the web site originally requested, one is allowed to enter, since the request now comes from a computer outside China.

The firewall censorship has been circumvented. This is possible as new computers are continually—and therefore uncontrollably for the government—keep entering the TOR network. This makes a national blocking of assigned IP addresses impossible, as they are ever changing with each new computer. The online magazine netzwelt.de offers detailed explanations and a step-by-step tutorial at www.netzwelt.de/news/74366 for downloading.

China-Cracker 2—Cracking the Firewall with the Help of Software from Outside China:

A more time-consuming and, so far, not as good a solution is the free program Psiphon. This software can be downloaded free of charge at www.netzwelt.de/software/7372. In contrast to the principle of the TOR network, Psiphon can only be used with greatest effort. Its mechanism is based on the idea that journalist xy is being supported by someone outside China, for example at the editorial office at home. This person installs the Psiphon software on a computer outside China. If the journalist in China wants to use the internet, he contacts that computer and enters the internet via this detour. Thereby, he can also visit pages which are blocked in China. One advantage of this method is that it needs no software directly on the PC in China. Possible software inspections by state censors would therefore come to nothing.

China-Cracker 3—Cracking the Firewall without Software Within and from Outside China:

Those not wanting to install specific software neither on their computer nor on an externalone to circumvent the firewall may also use so-called rewebbers. Those are specialinternet pages, for example www.proxify.com. In a sense, those providers replace theusual typing of an internet address into the Browser. Instead, one types the address of the desired web page into a separate field at www.proxify.com. The rewebber page will now channel the request for the website first through its own servers, before passing on the request to the actual web page.

The outcome: In the same way as the TOR network, rewebber pages do not allow to localize one's individual IP address according to the place from which one has called up a website (i.e. for instance China. Rather, the website accessed receives an IP address from the location of the rewebber site. A possible weak point: China could block the rewebber websites. Experts of the German IT online magazine netzwelt.de do not see this as a great obstacle, however. There are dozens of rewebber pages working according to the same principle, all being found very easily via search engines. Apart from Proxify, netzwelt.de also recommends for instance Anonymouse.org or Browseatwork.com.

China-Cracker 4—Encrypting Email, Hard Drives and Phone Calls against Spies:

Netzwelt.de has now shown the most important steps to regain freedom of press. One last problem remains, however: email correspondence. What counts here is the following message: emails by journalists in countries like China absolutely need to be send and received in encrypted fashion. China is known for having installed millions of Spyware programs on computers worldwide—for instance with the help of carelessly downloaded email attachments ostensibly sent by "good friends." For it is no longer a problem to fake even sender addresses of emails. How to encrypt one's email traffic may be learned from a separate netzwelt.de guide at www.netzwelt.de/news/78129.

Netzwelt.de recommends two free programs for the encryption of email. For one thing, the software GNuPG, which may be downloaded at www.netzwelt.de/software/7140, free of charge. As another program the netzwelt.de IT experts refer to the software Enigmail, which however only works with the Outlook alternative Mozilla Thunderbird (link: www.netzwelt.de/software/7139).

Links zum Artikel

Tags: Sicherheit, Software, Verschlüsselung, Proxy, Anonym im Netz

Top Virenschutz-Programme

Sicher im Internet

Wer seiner Standard-Software traut, der sollte sich nicht wundern, wenn plötzlich ein Virus oder Trojaner entdeckt wird. Netzwelt erklärt, wie man ein PC-System absichert.

Top Anti-Virus Vollversionen

Virenschutz

Welche Software den PC wirklich vor Viren schützt und welche Updates Sie auf jeden Fall installieren sollten, zeigen wir Ihnen in unserem ausführlichen Special zum Thema Virenschutz.

Email Sicherheit

Phishing ist wohl das bekannteste Phänomem, wenn es um Sicherheit und Emails geht. Dabei ist es so einfach seinen Mailer richtig einzustellen und damit die größten Gefahren direkt abzuwehren.