[2] The Great Firewall operates by checking transmission control protocol (TCP) packets for keywords or sensitive words.
[12] The techniques deployed by the Chinese government to maintain control of the Great Firewall can include modifying search results for terms, such as they did following Ai Weiwei’s arrest, and petitioning global conglomerates to remove content, as happened when they petitioned Apple to remove the Quartz business news publication’s app from its Chinese App Store after reporting on the 2019–2020 Hong Kong protests.
Nevertheless, the U.S. State Department has reported that the central government authorities have closely monitored Internet use in these regions,[16] and Hong Kong's National Security Law has been used to block websites documenting anti-government protests.
[18][19] A favorite saying of Deng Xiaoping's in the early 1980s, "If you open the window, both fresh air and flies will be blown in", is considered to be the political and ideological basis of the GFW Project.
Nonetheless, despite the economic freedom, values and political ideas of the Chinese Communist Party (CCP) have had to be protected by "swatting flies" of other unwanted ideologies.
Users are prohibited from using the Internet to create, replicate, retrieve, or transmit information that incites resistance to the PRC Constitution, laws, or administrative regulations; promoting the overthrow of the government or socialist system; undermining national unification; distorting the truth, spreading rumors, or destroying social order; or providing sexually suggestive material or encouraging gambling, violence, or murder.
On 6 December 2002, 300 people in charge of the GFW project from 31 provinces and cities throughout China participated in a four-day inaugural "Comprehensive Exhibition on Chinese Information System".
[25] At the exhibition, many western high-tech products, including Internet security, video monitoring and human face recognition were purchased.
[12][30] While the United States and several other western countries passed laws creating computer crimes beginning in the 1970s, China had no such legislation until 1997.
[32] The latter definition of online activities punishable under CL97, or "crimes carried out over computer networks", is used as justification for the Great Firewall, and can be cited when the government blocks any ISP, gateway connections, or any access to anything on the internet.
The central government relies heavily on its State Council regulators to determine what specific online behavior and speech fall under these definitions.
The project was completed in 2006, and is now carried out in buildings with machines operated by civilians and supervised by China's national police force, the Public Security Bureau (PSB).
The main operating procedures of the gatekeepers at the Golden Shield Project include monitoring domestic websites, email, and searching for politically sensitive language and calls to protest.
Minors (in China, those under the age of 18) are not allowed into Internet cafés, although this law is widely ignored, and when enforced, has spurred the creation of underground "Black Web Bars" visited by those underage.
[42] An illustrative but incomplete list of tactics includes: Because of the complexity involved in maintaining a large, up-to-date banned network list with dynamic IPs (and as this method has proven incompatible with services using content delivery networks) it is usually used as a last resort, with other blocking methods preferred (such as filtering based on QoS).
The vast majority of these fake responses contain public IP addresses of U.S. companies, including Facebook, Twitter, and Dropbox.
[47] Typical circumvention methods include modifying the Hosts file, typing the IP address instead of the domain name in a Web browser or using DNS over TLS/HTTPS.
It is currently in development by the IETF,[50] and is enabled by default for supported websites in Firefox and Chromium (Google Chrome, Microsoft Edge, Samsung Internet, and Opera).
[57] Side channel analysis seems to indicate that TCP Resets are coming from an infrastructure co-located or shared with QoS filtering routers.
[67] In addition to previously discussed techniques, the CAC is also using active probing in order to identify and block network services that would help escaping the firewall.
Article 15 of a 20 September 2000 document from the Chinese State Council, posted by the Xinhua News Agency, lists 9 categories of information which should be censored, blocked, or filtered from access to the citizens using the internet within China: To filter this content, the Chinese government not only uses its own blocking methods, but also heavily relies on internet companies, such as ISPs, social media operators such as Weibo,[82] and others to actively censor their users.
[83] This results in private companies censoring their own platform for filtered content, forcing Chinese internet users to use websites not hosted in China to access this information.
Because the monitoring of social media and chat apps in China presents a possibility of punishment for a user, the discussion of these topics is now limited to the thought of the Chinese Communist Party, or one's home and private spaces, reducing the chance for information about these topics to spread, reducing any threat of protest against the CCP.
She claims that, in the past 10 years, it has been increasingly difficult to access second opinions on events, meaning that students rarely have the opportunity to learn diverging viewpoints — only the "correct" thought of the CCP.
[93] The Great Firewall has also allowed China to develop its own major internet services, such as Tencent, Alibaba, Baidu,[95][96] Renren, Youku, and Weibo.
[97]: 8 China has its own version of many foreign web properties, for example: Bilibili and Tencent Video (YouTube), Weibo (Twitter), Moments[98] and Qzone (Facebook), WeChat (WhatsApp), Ctrip (Orbitz and others), and Zhihu[99] (Quora).
[124] Since at least 2015, the Russian Roskomnadzor agency collaborates with Chinese Great Firewall security officials in implementing its data retention and filtering infrastructure.
[128] Critics have argued that if other large countries begin following China's approach, the whole purpose of the creation of the Internet could be put in jeopardy.