Internet censorship circumvention#Software

Filters may block specific domain names, either using DNS hijacking or URL filtering. Sites are sometimes accessible through alternate names and addresses that may not be blocked.{{Cite web|url=https://freedomhouse.org/sites/default/files/inline_images/Censorship.pdf|title=Leaping Over the Firewall: A Review of Censorship Circumvention Tools|last1=Callanan|first1=Cormac|last2=Dries-Ziekenheiner|first2=Hein|date=2011-04-11|website=freedomhouse.org|language=en|access-date=2018-12-11|last3=Escudero-Pascual|first3=Alberto|last4=Guerra|first4=Robert|archive-url=https://web.archive.org/web/20190503064107/https://freedomhouse.org/sites/default/files/inline_images/Censorship.pdf|archive-date=3 May 2019|url-status=live}}

Some websites offer the same content at multiple pages or domain names.{{Cite news|url=https://ssd.eff.org/en/module/how-circumvent-online-censorship|title=How to: Circumvent Online Censorship|date=2014-08-05|work=Surveillance Self-Defense|access-date=2018-11-01|language=en|archive-url=https://web.archive.org/web/20181223084444/https://ssd.eff.org/en/module/how-circumvent-online-censorship|archive-date=23 December 2018|url-status=dead}} For example, the English Wikipedia is available at [https://en.wikipedia.org/ Main Page], and there is also a mobile-formatted version at [https://en.m.wikipedia.org/ Wikipedia, the free encyclopedia].

If DNS resolution is disrupted but the site is not blocked in other ways, it may be possible to access a site directly through its IP address or modifying the host file. Using alternative DNS servers, or public recursive name servers (especially when used through an encrypted DNS client), may bypass DNS-based blocking.

Censors may block specific IP addresses. Depending on how the filtering is implemented, it may be possible to use different forms of the IP address, such as by specifying the address in a different base.[http://www.notascoolasitseems.com/review/circumventing-network-filters-or-internet-censorship-using-simple-methods-vpns-and-proxies "Circumventing Network Filters Or Internet Censorship Using Simple Methods, VPNs, And Proxies"] {{Webarchive|url=https://web.archive.org/web/20111114152734/http://www.notascoolasitseems.com/review/circumventing-network-filters-or-internet-censorship-using-simple-methods-vpns-and-proxies|date=14 November 2011}}, Not As Cool As It Seems, 16 December 2009, accessed 16 September 2011 For example, the following URLs all access the same site, although not all browsers will recognize all forms: http://1.1.1.1/ (dotted decimal), http://16843009/ (decimal), http://0001.0001.0001.0001/ (dotted octal), http://1.1.1.1/ (hexadecimal), and http://0x01.0x01.0x01.0x01/ (dotted hexadecimal).

Blockchain technology is an attempt to decentralize namespaces outside the control of a single entity.{{Cite journal|last1=Kalodner|first1=Harry|last2=Carlsten|first2=Miles|last3=Ellenbogen|first3=Paul|last4=Bonneau|first4=Joseph|last5=Narayanan|first5=Arvind|title=An empirical study of Namecoin and lessons for decentralized namespace design|url=https://www.cs.princeton.edu/~arvindn/publications/namespaces.pdf|journal=Princeton University|pages=1–4}}{{Cite web|title=Squaring the Triangle: Secure, Decentralized, Human-Readable Names (Aaron Swartz's Raw Thought)|url=http://www.aaronsw.com/weblog/squarezooko.html|website=aaronsw.com|access-date=2020-05-03|archive-url=https://web.archive.org/web/20160305135446/http://www.aaronsw.com/weblog/squarezooko.html|archive-date=5 March 2016|url-status=live}} Decentralized namespaces enable censorship resistant domains. The BitDNS discussion began in 2010 with a desire to achieve names that are decentralized, secure and human readable.{{Cite web|title=BitDNS and Generalizing Bitcoin {{!}} Satoshi Nakamoto Institute|url=https://satoshi.nakamotoinstitute.org/posts/bitcointalk/threads/244/|website=satoshi.nakamotoinstitute.org|date=15 November 2010 |access-date=2020-05-03}}

Cached pages: Some search engines keep copies of previously indexed webpages, or cached pages, which are often hosted by search engines and may not be blocked.

Mirror and archive sites: Copies of web sites or pages may be available at mirror or archive sites such as the Internet Archive's Wayback Machine or Archive.today. The Docker Registry Image Repository is a centralized storage, application stateless, and node scalable HTTP public service and has a performance bottleneck in the multinational upload and download scenario. Decentralized Docker Registry avoids this centralization drawback. DDR uses a network-structured P2P network to store and query mirror manifest file and blob routing, while each node serves as an independent mirror repository to provide mirror upload and download for the entire network.{{Cite journal |last1=Xu |first1=Quanqing |last2=Jin |first2=Chao |last3=Rasid |first3=Mohamed Faruq Bin Mohamed |last4=Veeravalli |first4=Bharadwaj |last5=Aung |first5=Khin Mi Mi |date=2018 |title=Blockchain-based decentralized content trust for docker images |url=http://link.springer.com/10.1007/s11042-017-5224-6 |journal=Multimedia Tools and Applications |language=en |volume=77 |issue=14 |pages=18223–18248 |doi=10.1007/s11042-017-5224-6 |s2cid=21160524 |issn=1380-7501|url-access=subscription }}{{Cite web |date=2022-07-12 |title=Docker Registry |url=https://docs.docker.com/registry/ |access-date=2022-07-12 |website=Docker Documentation |language=en}}{{Cite journal |last1=Ovando-Leon |first1=Gabriel |last2=Veas-Castillo |first2=Luis |last3=Gil-Costa |first3=Veronica |last4=Marin |first4=Mauricio |date=2022-03-09 |title=Bot-Based Emergency Software Applications for Natural Disaster Situations |journal=Future Internet |language=en |volume=14 |issue=3 |pages=81 |doi=10.3390/fi14030081 |issn=1999-5903|doi-access=free }}

RSS aggregators: RSS aggregators such as Feedly may be able to receive and pass on RSS feeds that are blocked when accessed directly.[http://www.nartv.org/mirror/circ_guide.pdf Everyone's Guide to By-passing Internet Censorship] {{Webarchive|url=https://web.archive.org/web/20110915194455/http://www.nartv.org/mirror/circ_guide.pdf |date=15 September 2011 }}, The Citizen Lab, University of Toronto, September 2007

Decentralized Hosting: Content creators may publish to an alternative platform which is willing to host ones content. Napster was the first peer to peer platform but was closed due to centralized bootstrapping vulnerabilities. Gnutella was the first sustainable platform hosting by decentralization. Freenet's model is that "true freedom requires true anonymity." Later, BitTorrent was developed to allocate resources with high performance and fairness.Kent University: http://www.medianet.kent.edu/surveys/IAD06S-P2PArchitectures-chibuike/P2P%20App.%20Survey%20Paper.htm ZeroNet was the first DHT to support dynamic and updateable webpages. YaCy is the leading distributed search.

Anonymity Networks: The anonymity Tor network and I2P provides leads to more willingness to host content that would otherwise be censored. However hosting implementation and location may bring issues, and the content is still hosted by a single entity which can be controlled.

{{Main|Fediverse}}

Federated: Being semi-decentralized, federated platforms such as Nextcloud and IRC make it easier for users to find an instance where they are welcomed.

Providers with a different policy: Some platforms relying on the Cloud may have more lax TOS. However nothing by design keeps it so.

See: Darknets

Web proxies allow users to load external web pages through the proxy server, permitting the user to load the page as if it is coming from the proxy server and not the (blocked) source. Depending on how the proxy is configured, a censor may be able to determine the pages loaded or determine that the user is using a proxy server.

For example, the mobile Opera Mini browser uses proxies with employing encryption and compression to speed up downloads. This has the side effect of circumventing several approaches to Internet censorship. In 2009 this led the government of China to ban all but a special Chinese version of the browser.{{cite web|title=Opera accused of censorship, betrayal by Chinese users|work=CNet Asia|author=Steven Millward|date=22 November 2009|url=http://asia.cnet.com/blogs/opera-accused-of-censorship-betrayal-by-chinese-users-62115913.htm|url-status=dead|archive-url=https://web.archive.org/web/20131103151615/http://asia.cnet.com/blogs/opera-accused-of-censorship-betrayal-by-chinese-users-62115913.htm|archive-date=3 November 2013}}

Domain fronting: Domain fronting hides the destination of a connection by passing initial requests through a content delivery network or other popular site which censors may be unwilling to block.{{Cite journal|last1=Fifield|first1=David|last2=Lan|first2=Chang|last3=Hynes|first3=Rod|last4=Wegmann|first4=Percy|last5=Paxson|first5=Vern|date=2015-06-01|title=Blocking-resistant communication through domain fronting|journal=Proceedings on Privacy Enhancing Technologies|language=en|volume=2015|issue=2|pages=46–64|doi=10.1515/popets-2015-0009|issn=2299-0984|doi-access=free}} This technique was used by messaging applications including Signal and Telegram. Tor's meek uses Microsoft's Azure cloud. However, large cloud providers such as Amazon Web Services and Google Cloud no longer permit its use.{{Cite web|url=https://www.bloomberg.com/opinion/articles/2018-05-03/telegram-block-gets-help-from-google-and-amazon|title=Russian Censor Gets Help From Amazon and Google|last=Bershidsky|first=Leonid|date=3 May 2018|publisher=Bloomberg L.P.|access-date=9 November 2018|archive-url=https://web.archive.org/web/20181118081519/https://www.bloomberg.com/opinion/articles/2018-05-03/telegram-block-gets-help-from-google-and-amazon|archive-date=18 November 2018|url-status=live}} Website owners can use a free account to use a Cloudflare domain for fronting.{{Cite web|url=https://en.greatfire.org/blog/2012/may/how-unblock-websites-china-web-owners|title=How to unblock websites in China for web owners {{pipe}} GreatFire Analyzer|website=en.greatfire.org|access-date=6 January 2020|archive-url=https://web.archive.org/web/20200325044044/https://en.greatfire.org/blog/2012/may/how-unblock-websites-china-web-owners|archive-date=25 March 2020|url-status=live}}{{Cite web|url=https://medium.com/@themiddleblue/cloudflare-domain-fronting-an-easy-way-to-reach-and-hide-a-malware-c-c-786255f0f437|title=CloudFlare Domain Fronting: an easy way to reach (and hide) a malware C&C|date=11 August 2017|website=Medium|access-date=6 January 2020|archive-url=https://web.archive.org/web/20191119193400/https://medium.com/@themiddleblue/cloudflare-domain-fronting-an-easy-way-to-reach-and-hide-a-malware-c-c-786255f0f437|archive-date=19 November 2019|url-status=live}}

SSH tunneling: By establishing an SSH tunnel, a user can forward all their traffic over an encrypted channel, so both outgoing requests for blocked sites and the response from those sites are hidden from the censors, for whom it appears as unreadable SSH traffic.{{Cite web|url=https://www.howtogeek.com/168145/how-to-use-ssh-tunneling/|title=How to Use SSH Tunneling to Access Restricted Servers and Browse Securely|last=Hoffman|first=Chris|website=How-To Geek|date=14 February 2017 |language=en-US|access-date=2018-12-11|archive-url=https://web.archive.org/web/20181215172356/https://www.howtogeek.com/168145/how-to-use-ssh-tunneling/|archive-date=15 December 2018|url-status=live}}

Virtual private network (VPN): Using a VPN, secure connections to more permissive countries can be created, browsing as if they were situated in that country. Some services are offered for a monthly fee; others are ad-supported. According to GlobalWebIndex in 2014 there were over 400 million people using virtual private networks to circumvent censorship or for increased level of privacy, although this number is not verifiable.

Tor: More advanced tools such as Tor route encrypted traffic through multiple servers to make the source and destination of traffic less traceable. It can in some cases be used to avoid censorship, especially when configured to use traffic obfuscation techniques.{{Cite journal|last1=Dixon|first1=Lucas|last2=Ristenpart|first2=Thomas|last3=Shrimpton|first3=Thomas|date=14 December 2016|title=Network Traffic Obfuscation and Automated Internet Censorship|journal=IEEE Security & Privacy|language=en-US|volume=14|issue=6|pages=43–53|doi=10.1109/msp.2016.121|issn=1540-7993|arxiv=1605.04044|s2cid=1338390}}

File:Tor_Pluggable_Transport_Directions.png

A censor may be able to detect and block use of circumvention tools through deep packet inspection.{{cite journal |last1=Bateyko |first1=Dan |title=Censorship-Circumvention Tools and Pluggable Transports |journal=Georgetown Law Technology Review |date=February 2022 |url=https://georgetownlawtechreview.org/censorship-circumvention-tools-and-pluggable-transports/GLTR-02-2022/ |access-date=2 December 2023}} There are efforts to make circumvention tools less detectable by randomizing the traffic, attempting to mimic a whitelisted protocol or tunnelling traffic through a whitelisted site by using domain fronting or Meek. Tor and other circumvention tools have adopted multiple obfuscation techniques that users can use depending on the nature of their connection, which are sometimes called "Pluggable Transports".{{Cite book|last1=Shahbar|first1=K.|last2=Zincir-Heywood|first2=A. N.|title=2015 11th International Conference on Network and Service Management (CNSM) |chapter=Traffic flow analysis of tor pluggable transports |date=2015-11-09|pages=178–181|doi=10.1109/CNSM.2015.7367356|isbn=978-3-9018-8277-7|s2cid=1199826}}

Functionality that people may be after might overlap with non-internet services, such as traditional mail, Bluetooth, or walkie-talkies. The following are some detailed examples:

Datacasting allows transmission of Web pages and other information via satellite broadcast channels bypassing the Internet entirely. This requires a satellite dish and suitable receiver hardware but provides a powerful means of avoiding censorship. Because the system is entirely receive-only for the end user, a suitably air-gapped computer can be impossible to detect.{{cite web |last1=Tanase |first1=Stefan |title=Satellite Turla: APT Command and Control in the Sky |url=https://securelist.com/satellite-turla-apt-command-and-control-in-the-sky/72081/ |website=Kaspersky |date=9 September 2015 |access-date=17 August 2020}}

A sneakernet is the transfer of electronic information, especially computer files, by physically carrying data on storage media from one place to another. A sneakernet can move data regardless of network restrictions simply by not using the network at all.Sullivan, Bob (13 April 2006) [http://redtape.msnbc.com/2006/04/military_thumb_.html Military Thumb Drives Expose Larger Problem] {{Webarchive|url=https://web.archive.org/web/20101206124100/http://redtape.msnbc.com/2006/04/military_thumb_.html |date=6 December 2010 }} MSNBC Retrieved on 25 January 2007. One example of a widely adopted sneakernet network is El Paquete Semanal in Cuba.{{Cite web|url=https://www.cbc.ca/news/world/cuba-el-paquete-internet-wifi-havana-1.3527274|title=When Cubans want internet content, black-market El Paquete delivers |date=12 April 2016|first=Matt|last=Kwong|publisher=Canadian Broadcasting Corporation|language=en|access-date=2018-12-11|archive-url=https://web.archive.org/web/20190108010845/https://www.cbc.ca/news/world/cuba-el-paquete-internet-wifi-havana-1.3527274|archive-date=8 January 2019|url-status=live}}

Circumvention tools have seen spikes in adoption in response to high-profile blocking attempts,{{Cite web|url=https://blogs.wsj.com/digits/2014/03/21/from-pac-man-to-bird-droppings-turkey-protests-twitter-ban/|title=From Pac-Man to Bird Droppings, Turkey Protests Twitter Ban|last=Edwards|first=John|date=2014-03-21|website=The Wall Street Journal|language=en-US|access-date=2018-11-15|archive-url=https://web.archive.org/web/20181215225518/https://blogs.wsj.com/digits/2014/03/21/from-pac-man-to-bird-droppings-turkey-protests-twitter-ban/|archive-date=15 December 2018|url-status=live}}{{Cite journal|last1=Kargar|first1=Simin|last2=McManamen|first2=Keith|date=2018|title=Censorship and Collateral Damage: Analyzing the Telegram Ban in Iran|journal=SSRN Working Paper Series|language=en|doi=10.2139/ssrn.3244046|issn=1556-5068|ssrn=3244046|s2cid=159020053}}{{cite journal|last1=Al-Saqaf|first1=Walid|title=Internet Censorship Circumvention Tools: Escaping the Control of the Syrian Regime|journal=Media and Communication|volume=4|issue=1|pages=39–50|doi=10.17645/mac.v4i1.357|year=2016|doi-access=free}} however, studies measuring adoption of circumvention tools in countries with persistent and widespread censorship report mixed results.{{Cite web|url=https://cyber.harvard.edu/publications/2010/Circumvention_Tool_Usage|title=2010 Circumvention Tool Usage Report|website=Berkman Klein Center|date=19 June 2018 |language=en|access-date=2018-11-15|archive-url=https://web.archive.org/web/20181215224933/https://cyber.harvard.edu/publications/2010/Circumvention_Tool_Usage|archive-date=15 December 2018|url-status=live}}

Measures and estimates of circumvention tool adoption have found widely divergent results. A 2010 study by Harvard University researchers estimated that very few users use censorship circumvention tools—likely less than 3% of users even in countries that consistently implement widespread censorship. Other studies have reported substantially larger estimates, but have been disputed.

In China, anecdotal reports suggest that adoption of circumvention tools is particularly high in certain communities, such as universities,{{Cite news|url=https://www.scmp.com/news/china/policies-politics/article/2103793/vpn-crackdown-unthinkable-trial-firewall-chinas|title=VPN crackdown a trial by firewall for China's research world|work=South China Morning Post|access-date=2018-11-15|language=en|archive-url=https://web.archive.org/web/20181218203632/https://www.scmp.com/news/china/policies-politics/article/2103793/vpn-crackdown-unthinkable-trial-firewall-chinas|archive-date=18 December 2018|url-status=live}}{{Cite news|url=https://www.theguardian.com/world/2011/feb/18/china-great-firewall-not-secure-internet|title=China's Great Firewall not secure enough, says creator|last=Branigan|first=Tania|date=2011-02-18|work=The Guardian|access-date=2018-12-11|language=en-GB|issn=0261-3077|archive-url=https://web.archive.org/web/20181216031025/https://www.theguardian.com/world/2011/feb/18/china-great-firewall-not-secure-internet|archive-date=16 December 2018|url-status=live}} and a survey by Freedom House found that users generally did not find circumvention tools to be difficult to use. Market research firm GlobalWebIndex reported over 35 million Twitter users and 63 million Facebook users in China (both services are blocked). However, these estimates have been disputed;{{Cite news|url=https://www.theguardian.com/technology/2014/dec/05/how-faceboook-tor-service-encourage-open-web|title=How Facebook's Tor service could encourage a more open web|last=Mari|first=Marcello|date=2014-12-05|work=The Guardian|access-date=2018-12-13|language=en-GB|issn=0261-3077|archive-url=https://web.archive.org/web/20160610180205/https://www.theguardian.com/technology/2014/dec/05/how-faceboook-tor-service-encourage-open-web|archive-date=10 June 2016|url-status=live}} Facebook's advertising platform estimates 1 million users in China, and other reports of Twitter adoption estimate 10 million users.{{Cite web|url=https://techcrunch.com/2016/07/05/twitter-estimates-that-it-has-10-million-users-in-china/ |first1=Jon |last1=Russell |title=Twitter estimates that it has 10 million users in China|website=TechCrunch|date=5 July 2016 |language=en-US|access-date=2018-12-11|archive-url=https://web.archive.org/web/20190128091631/https://techcrunch.com/2016/07/05/twitter-estimates-that-it-has-10-million-users-in-china/|archive-date=28 January 2019|url-status=live}} Other studies have pointed out that efforts to block circumvention tools in China have reduced adoption of those tools; the Tor network previously had over 30,000 users connecting from China but as of 2014 had only approximately 3,000 Chinese users.{{Cite journal|last1=Crandall|first1=Jedidiah R.|last2=Mueen|first2=Abdullah|last3=Winter|first3=Philipp|last4=Ensafi|first4=Roya|date=2015-04-01|title=Analyzing the Great Firewall of China Over Space and Time|journal=Proceedings on Privacy Enhancing Technologies|language=en|volume=2015|issue=1|pages=61–76|doi=10.1515/popets-2015-0005|doi-access=free |url=https://petsymposium.org/popets/2015/popets-2015-0005.php |url-status=live |archive-url=https://web.archive.org/web/20231203042208/https://petsymposium.org/popets/2015/popets-2015-0005.php |archive-date= Dec 3, 2023 }}

In Thailand, internet censorship has existed since 2002, and there is sporadic and inconsistent filtering.{{Cite book|title=Access contested : security, identity, and resistance in Asian cyberspace information revolution and global politics|date=2012|publisher=MIT Press|editor-last1=Deibert |editor-first1=Ronald |isbn=9780262298919|location=Cambridge, MA|pages=85|oclc=773034864}} In a small-scale survey of 229 Thai internet users, a research group at the University of Washington found that 63% of surveyed users attempted to use circumvention tools, and 90% were successful in using those tools. Users often made on-the-spot decisions about use of circumvention tools based on limited or unreliable information, and had a variety of perceived threats, some more abstract and others based on personal experiences.{{Cite book|last1=Gebhart|first1=Genevieve|last2=Kohno|first2=Tadayoshi|title=2017 IEEE European Symposium on Security and Privacy (EuroS&P) |chapter=Internet Censorship in Thailand: User Practices and Potential Threats |date=26 April 2017|pages=417–432 |language=en-US|publisher=IEEE|doi=10.1109/eurosp.2017.50|isbn=9781509057627|s2cid=11637736}}

In response to the 2014 blocking of Twitter in Turkey, information about alternate DNS servers was widely shared, as using another DNS server such as Google Public DNS allowed users to access Twitter.{{Cite news|url=https://www.theverge.com/2014/3/21/5532522/turkey-twitter-ban-google-dns-workaround |first1= Aaron |last1=Souppouris |date=Mar 21, 2014 |title=Turkish citizens use Google to fight Twitter ban|work=The Verge|access-date=2018-11-15|archive-url=https://web.archive.org/web/20190108010839/https://www.theverge.com/2014/3/21/5532522/turkey-twitter-ban-google-dns-workaround|archive-date=8 January 2019|url-status=live}} The day after the block, the total number of posts made in Turkey was up 138%, according to Brandwatch, an internet measurement firm.

After an April 2018 ban on the Telegram messaging app in Iran, web searches for VPN and other circumvention software increased as much as 48x for some search terms, but there was evidence that users were downloading unsafe software. As many as a third of Iranian internet users used the Psiphon tool in the days immediately following the block, and in June 2018 as many as 3.5 million Iranian users continued to use the tool.

Circumvention and anonymity are different. Circumvention systems are designed to bypass blocking, but they do not usually protect identities. Anonymous systems protect a user's identity, and while they can contribute to circumvention, that is not their primary function. Open public proxy sites do not provide anonymity and can view and record the location of computers making requests as well as the websites accessed.

In many jurisdictions accessing blocked content is a serious crime, particularly content that is considered to be child pornography, a threat to national security, or an incitement of violence. Thus it is important to understand the circumvention technologies and the protections they do or do not provide and to use only tools that are appropriate in a particular context. Great care must be taken to install, configure, and use circumvention tools properly. Individuals associated with high-profile rights organizations, dissident, protest, or reform groups should take extra precautions to protect their online identities.

Circumvention sites and tools should be provided and operated by trusted third parties located outside the censoring jurisdiction that do not collect identities and other personal information. Trusted family and friends personally known to the circumventor are best, but when family and friends are not available, sites and tools provided by individuals or organizations that are only known by their reputations or through the recommendations and endorsement of others may need to be used. Commercial circumvention services may provide anonymity while surfing the Internet, but could be compelled by law to make their records and users' personal information available to law enforcement.

There are five general types of Internet censorship circumvention software:

CGI proxies use a script running on a web server to perform the proxying function. A CGI proxy client sends the requested URL embedded within the data of HTTP requests to the CGI proxy server. The CGI proxy server sends out its own HTTP request to the ultimate destination, and then returns the result to the proxy client. A CGI proxy tool's security can be trusted as far as the operator of the proxy server can be trusted. CGI proxy tools require no manual configuration of the browser or client software installation, but they do require that the user use an alternative, potentially confusing browser interface within the existing browser.

HTTP proxies send HTTP requests through an intermediate proxying server. A client connecting through a HTTP proxy sends exactly the same HTTP request to the proxy as it would send to the destination server unproxied. The HTTP proxy parses the HTTP request; sends its own HTTP request to the ultimate destination server; and then returns the response back to the proxy client. An HTTP proxy tool's security can be trusted as far as the operator of the proxy server can be trusted. HTTP proxy tools require either manual configuration of the browser or client side software that can configure the browser for the user. Once configured, an HTTP proxy tool allows the user transparently to use his normal browser interface.

Application proxies are similar to HTTP proxies, but support a wider range of online applications.

Peer-to-peer systems store content across a range of participating volunteer servers combined with technical techniques such as re-routing to reduce the amount of trust placed on volunteer servers or on social networks to establish trust relationships between server and client users. Peer-to-peer system can be trusted as far as the operators of the various servers can be trusted or to the extent that the architecture of the peer-to-peer system limits the amount of information available to any single server and the server operators can be trusted not to cooperate to combine the information they hold.

Re-routing systems send requests and responses through a series of proxying servers, encrypting the data again at each proxy, so that a given proxy knows at most either where the data came from or is going to, but not both. This decreases the amount of trust required of the individual proxy hosts.

Below is a list of different Internet censorship circumvention software:

{{Portal|Internet|Freedom of speech}}

{{div col|colwidth=35em}}

• Anonymous P2P
• Bypassing content-control filters
• Computer surveillance
• Content-control software
• Crypto-anarchism
• Cypherpunk
• Electronic Frontier Foundation – an international non-profit digital rights advocacy and legal organization
• Freedom of information
• Freedom of speech
• Global Internet Freedom Consortium (GIFC) – a consortium of organizations that develop and deploy anti-censorship technologies
• Bypassing the Great Firewall of China
• Internet freedom
• Internet privacy
• Mesh networking
• Open Technology Fund (OTF) – a U.S. Government funded program created in 2012 at Radio Free Asia to support global Internet freedom technologies
• Proxy list
• Tactical Technology Collective – a non-profit foundation promoting the use of free and open source software for non-governmental organizations, and producers of NGO-in-A-Box

{{div col end}}

{{Reflist|33em|refs=

Marcello Mari. [https://www.theguardian.com/technology/2014/dec/05/how-faceboook-tor-service-encourage-open-web How Facebook's Tor service could encourage a more open web] {{Webarchive|url=https://web.archive.org/web/20160610180205/https://www.theguardian.com/technology/2014/dec/05/how-faceboook-tor-service-encourage-open-web |date=10 June 2016 }}. The Guardian. Friday 5 December 2014.

}}

{{Commons category |Internet censorship}}

• [https://munkschool.utoronto.ca/downloads/casting.pdf Casting A Wider Net: Lessons Learned in Delivering BBC Content on the Censored Internet] {{Webarchive|url=https://web.archive.org/web/20221003061609/https://munkschool.utoronto.ca/downloads/casting.pdf |date=3 October 2022 }}, Ronald Deibert, Canada Centre for Global Security Studies and Citizen Lab, Munk School of Global Affairs, University of Toronto, 11 October 2011
• [http://censorship.wikia.com/ Censorship Wikia], an anti-censorship site that catalogs past and present censored works, using verifiable sources, and a forum to discuss organizing against and circumventing censorship
• [http://cyber.law.harvard.edu/publications/2011/2011_Circumvention_Tool_Evaluation "Circumvention Tool Evaluation: 2011"], Hal Roberts, Ethan Zuckerman, and John Palfrey, Berkman Centre for Internet & Society, 18 August 2011
• [https://cyber.harvard.edu/publications/2010/Circumvention_Tool_Usage "Circumvention Tool Usage Report: 2010"], Hal Roberts, Ethan Zuckerman, Jillian York, Robert Faris, and John Palfrey, Berkman Centre for Internet & Society, 14 October 2010
• [https://equalit.ie/esecman/ Digital Security and Privacy for Human Rights Defenders], by Dmitri Vitaliev, Published by Front Line – The International Foundation for the Protection of Human Rights Defenders
• [https://www.nytimes.com/2013/07/18/technology/personaltech/digital-tools-to-help-curb-online-eavesdropping.html "Digital Tools to Curb Snooping"], The New York Times, 17 July 2013
• [https://web.archive.org/web/20170606184350/https://www.ab9il.net/crypto/dns-swapping.html "DNS Nameserver Swapping"], Methods and Scripts useful for evading censorship through DNS filtering
• [https://archive.flossmanuals.net/bypassing-censorship/ How to Bypass Internet Censorship], also known by the titles: Bypassing Internet Censorship or Circumvention Tools, a FLOSS Manual, 10 March 2011, 240 pp. Translations have been published in [https://web.archive.org/web/20111225125113/http://en.flossmanuals.net/bypassing-ar/ Arabic], [https://web.archive.org/web/20160810232825/http://en.flossmanuals.net/circumvention-tools-mn/ Burmese], [https://web.archive.org/web/20160811214703/http://en.flossmanuals.net/circumvention-tools-zh/ Chinese], [https://web.archive.org/web/20160413172012/http://en.flossmanuals.net/bypassing-fa/ Persian], [https://web.archive.org/web/20160813152646/http://en.flossmanuals.net/bypassing-ru/ Russian], [http://booki.flossmanuals.net/bypassing-es/ Spanish], and [https://web.archive.org/web/20161015103759/http://en.flossmanuals.net/bypassing-vi/ Vietnamese]
• [http://freedomhouse.org/uploads/special_report/97.pdf "Leaping over the Firewall: A Review of Censorship Circumvention Tools"] {{Webarchive|url=https://web.archive.org/web/20110915201024/http://freedomhouse.org/uploads/special_report/97.pdf |date=15 September 2011 }}, by Cormac Callanan (Ireland), Hein Dries-Ziekenheiner (Netherlands), Alberto Escudero-Pascual (Sweden), and Robert Guerra (Canada), Freedom House, April 2011
• [http://www.osce.org/fom/13836 "Media Freedom Internet Cookbook"] by the OSCE Representative on Freedom of the Media, Vienna, 2004
• [https://web.archive.org/web/20130806230600/https://www.wefightcensorship.org/online-survival-kithtml.html "Online Survival Kit"], We Fight Censorship project of Reporters Without Borders
• [http://freehaven.net/anonbib/topic.html "Selected Papers in Anonymity"], Free Haven Project, accessed 16 September 2011

{{Censorship}}

{{Internet censorship}}

{{Censorship and websites}}

{{Internet censorship circumvention technologies}}

{{DEFAULTSORT:Internet Censorship Circumvention}}

Category:Internet security

Category:Content-control software

Category:Internet censorship

Category:Internet privacy

Category:Circumvention