Original author(s) | Serene |
---|---|
Developer(s) | The Tor Project and community |
Initial release | January 24, 2017 [1] |
Repository | |
Written in | Go, [2] [3] JavaScript [2] [4] |
Included with | Tor Browser, [1] Orbot [1] |
Predecessor | Flash proxy [1] |
Type | Internet censorship circumvention, [1] Overlay network [ citation needed ] |
License | 3-clause BSD License [5] [4] [6] |
Website | snowflake |
Snowflake is a software package for assisting others in circumventing internet censorship by relaying data requests. Snowflake proxy nodes are meant to be created by people in countries where Tor and Snowflake are not blocked. [7] People under censorship then use a Snowflake client, packaged with the Tor Browser or Onion Browser, [8] to access the Tor network, using Snowflake relays as proxy servers. Access to the Tor network can in turn give access to other blocked services (like blocked websites). [7] A Snowflake proxy can be created by either installing a browser extension, installing a stand-alone program, or browsing a webpage with an embedded Snowflake proxy. The proxy runs whenever the browser or program is connected to the internet.
In contrast to regular VPNs and proxy services, launching a Snowflake proxy does not require port forwarding or having a dedicated IP address. [1] Simply installing the browser extension is enough most of the time. The simplicity of launching a proxy warrants their numerosity, which makes it hard for the censors to block proxies by simply blocking their IP addresses. [1] [9]
As of 2024, Snowflake proxies are hosted on about 140 000 IP unique addresses concurrently. [1] The average number of users that use Snowflake to connect to Tor is 35 000 and 29 TB of their traffic is relayed by Snowflake proxies daily. [1]
Tor is itself illegal in some countries. Like the internet, it can relay any sort of content, and some types of content are illegal in some countries.
Snowflake was originated by Serene, a hacker and former Google engineer and concert pianist. [10] It was inspired by Flash proxy, a similar censorship circumvention system. [11] The name "Snowflake" was coined as her metaphor for a large number of ephemeral proxies [7] in relation to "ICE Negotiation". [11] Three programmers published the first version in January 2016. In 2019, it became available as a browser extension for Firefox and Chrome. [7] It can also be run on derived browsers, such as Brave and Microsoft Edge. [12] [8] In February 2023 a thoroughly upgraded, stand-alone version dubbed Snowstorm was released; written in Rust and funded by the Open Tech Fund, beta testing is by invitation. [13] [14]
Normal internet data packages come labelled with the original source and the final recipient of the data. For example, a package containing the encrypted text of this article would be labelled with the destination (the IP address of the reader's computer), and the source (the IP address of a Wikipedia server). [15] [16] This means that even if the actual content is encrypted, a censor can block all packages from certain sources (for instance, banning any package that comes from Wikipedia). [17] [18] [19]
Tor network can be used to access such blocked sites [16] by acting as a proxy, covering the real destination address of the user's request. [20] [21] This is why censors usually try to block the Tor network as well. [16] It is fairly easy for censors to block direct access to Tor because all regular Tor relays are public. [16]
Snowflake provides covert, indirect access to Tor. [1] A Snowflake client is provided with the IP address of a currently-active Snowflake proxy by asking a broker server, [8] [22] which in turn uses domain fronting to pretend to be a major website. The client then talks directly to the Snowflake proxy, which relays into the Tor network. The traffic looks like ordinary peer-to-peer traffic, such as that used by many videoconferencing apps. [22]
A Snowflake proxy runs whenever the browser or program is connected to the internet. If the proxy host has a dynamic IP, the proxy will change its IP address over time. [10] [8] See also ad hoc network.
Snowflake proxies are thus used as Tor entry nodes, not as exit nodes. Exit nodes are the other end of the chain. They are the Tor nodes that know what content was requested, though they do not know who requested it (for instance, they would know that someone was contacting a Wikipedia server, but they would not know the IP address of the user). Exit nodes might face legal action in the country in which they are hosted if they relay content that is illegal in that country (so they are usually run in countries with little internet censorship). It is unlikely that Snowflake proxy hosts could face such liability, since they do not know what content they are relaying. [10] There are, however, countries where using Tor for any purpose is illegal, such as Russia and Iran. [23]
<iframe src="https://snowflake.torproject.org/embed.html" width="320" height="240" frameborder="0" scrolling="no"></iframe>
— snowflake.torproject .org ,
HTML code to add a togglable Snowflake relay to a webpage
Snowflake uses WebRTC to allow browsers to communicate directly with one another. [8] Either installing a browser extension, or keeping a tab open to a webpage with the right embedded code, causes one's browser to act as a proxy. [7] Embedding a Snowflake badge in a website allows visitors to make their browser into a proxy, exactly as installing the extension does, but by clicking a button on the website rather than by installing software. [24] Snowflake can also be run as a stand-alone program in a Docker container. [8]
Proxying traffic increases the proxy host's bandwidth usage, which may be a problem for those with bandwidth limits on their internet plans. [10] In practice, hosting a Snowflake proxy does not seem to appreciably slow one's internet connection [12] or disrupt browsing. [8]
A detailed technical description is published on GitLab. [25]
Countermeasures believed to be currently in use against Snowflake from Russia include browser fingerprinting Snowflake hosts and then blocking them. Censors may also install and use Tor, then block all the IP addresses offered as Snowflake servers. Both of these techniques are weakened when there are larger numbers of servers. [26]
Censors may attempt to block the broker's IP address. To circumvent this, the Snowflake client utilizes domain fronting. This makes it infeasible for the censor to block a single website without blocking all the other websites hosted on the same cloud service. Google and Amazon are examples of such services. They host hundreds of thousands of websites. Blocking all the servers of one of these major hosts has disruptive side effects. [22] However, the cloud provider can and often does block domain fronting. [27] [28]
If overseas connections from data centers are allowed, but residential and mobile services are restricted to local connections, then Tor bridges may be secretly and illegally set up in local data centers. This has obvious dangers. [29]
When a country shuts down access to foreign internet connections altogether, essentially cutting the country off from the global internet, Snowflake becomes useless. [10] This has been repeatedly done in Iran and some other countries; it is, however, bad for business (in Iran in 2022, the cost was estimated at $37 million US a day [30] ), so it is usually only done for short periods. [10] [31]
A simple proxy, like a virtual private network (VPN), has only a single relay. This means that the server address of the VPN has to be known to every user, making it easier to block. [10] For instance, at the beginning of October 2022, during internet disruptions related to the Mahsa Amini protests, VPNs in Iran would drop connections every few minutes. [29] The VPN itself also knows which end-users requested which pages, allowing VPNs to engage in surveillance. [10] [32] In some countries, such as Iran, VPNs are illegal [10] and may be government-affiliated. [30]
Snowflake came to be widely discussed online in the first week of October 2022, as a way of combatting internet restrictions in Iran during the Mahsa Amini protests, [10] and a guide in Persian was released. [33] [22]
In 2022, the Russian government increased efforts to block access to Tor through technical and political means, and the Tor network reported an increase in traffic from Russia using Snowflake. [26]
Snowflake is integrated into the Tor network. Usage of the Tor network is becoming more common in Russia, Belarus, and Iran, as of 2022 [update] , as internet censorship in these countries has become more strict. [12]
In computer networking, a proxy server is a server application that acts as an intermediary between a client requesting a resource and the server providing that resource. It improves privacy, security, and possibly performance in the process.
China censors both the publishing and viewing of online material. Many controversial events are censored from news coverage, preventing many Chinese citizens from knowing about the actions of their government, and severely restricting freedom of the press. China's censorship includes the complete blockage of various websites, apps, and video games, inspiring the policy's nickname, the Great Firewall of China, which blocks websites. Methods used to block websites and pages include DNS spoofing, blocking access to IP addresses, analyzing and filtering URLs, packet inspection, and resetting connections.
SOCKS is an Internet protocol that exchanges network packets between a client and server through a proxy server. SOCKS5 optionally provides authentication so only authorized users may access a server. Practically, a SOCKS server proxies TCP connections to an arbitrary IP address, and provides a means for UDP packets to be forwarded. A SOCKS server accepts incoming client connection on TCP port 1080, as defined in RFC 1928.
IP address blocking or IP banning is a configuration of a network service that blocks requests from hosts with certain IP addresses. IP address blocking is commonly used to protect against brute force attacks and to prevent access by a disruptive address. It can also be used to restrict access to or from a particular geographic area; for example, syndicating content to a specific region through the use of Internet geolocation.
The Great Firewall is the combination of legislative actions and technologies enforced by the People's Republic of China to regulate the Internet domestically. Its role in internet censorship in China is to block access to selected foreign websites and to slow down cross-border internet traffic. The Great Firewall operates by checking transmission control protocol (TCP) packets for keywords or sensitive words. If the keywords or sensitive words appear in the TCP packets, access will be closed. If one link is closed, more links from the same machine will be blocked by the Great Firewall. The effect includes: limiting access to foreign information sources, blocking foreign internet tools and mobile apps, and requiring foreign companies to adapt to domestic regulations.
An open proxy is a type of proxy server that is accessible by any Internet user.
.onion is a special-use top-level domain name designating an anonymous onion service, which was formerly known as a "hidden service", reachable via the Tor network. Such addresses are not actual DNS names, and the .onion TLD is not in the Internet DNS root, but with the appropriate proxy software installed, Internet programs such as web browsers can access sites with .onion addresses by sending the request through the Tor network.
Freegate is a software application developed by Dynamic Internet Technology (DIT) that enables internet users to view websites blocked by their governments. The program takes advantage of a range of proxy servers called Dynaweb. This allows users to bypass Internet firewalls that block web sites by using DIT's Peer-to-peer (P2P)-like proxy network system. FreeGate's anti-censorship capability is further enhanced by a new, unique encryption and compression algorithm in the versions of 6.33 and above. Dynamic Internet Technology estimates Freegate had 200,000 users in 2004. The maintainer and CEO of DIT is Bill Xia.
Internet censorship is the legal control or suppression of what can be accessed, published, or viewed on the Internet. Censorship is most often applied to specific internet domains but exceptionally may extend to all Internet resources located outside the jurisdiction of the censoring state. Internet censorship may also put restrictions on what information can be made internet accessible. Organizations providing internet access – such as schools and libraries – may choose to preclude access to material that they consider undesirable, offensive, age-inappropriate or even illegal, and regard this as ethical behavior rather than censorship. Individuals and organizations may engage in self-censorship of material they publish, for moral, religious, or business reasons, to conform to societal norms, political views, due to intimidation, or out of fear of legal or other consequences.
An anonymizer or an anonymous proxy is a tool that attempts to make activity on the Internet untraceable. It is a proxy server computer that acts as an intermediary and privacy shield between a client computer and the rest of the Internet. It accesses the Internet on the user's behalf, protecting personal information of the user by hiding the client computer's identifying information such as IP addresses. Anonymous proxy is the opposite of transparent proxy, which sends user information in the connection request header. Commercial anonymous proxies are usually sold as VPN services.
Tor is a free overlay network for enabling anonymous communication. Built on free and open-source software and more than seven thousand volunteer-operated relays worldwide, users can have their Internet traffic routed via a random path through the network.
Internet censorship circumvention is the use of various methods and tools to bypass internet censorship.
Flash proxy is a pluggable transport and proxy which runs in a web browser. Flash proxies are an Internet censorship circumvention tool which enables users to connect to the Tor anonymity network via a plethora of ephemeral browser-based proxy relays. The essential idea is that the IP addresses contingently used are changed faster than a censoring agency can detect, track, and block them. The Tor traffic is wrapped in a WebSocket format and disguised with an XOR cipher.
VPN blocking is a technique used to block the encrypted protocol tunneling communications methods used by virtual private network (VPN) systems. Often used by large organizations such as national governments or corporations, it can act as a tool for computer security or Internet censorship by preventing the use of VPNs to bypass network firewall systems.
Hotspot Shield is a public VPN service operated by AnchorFree, Inc. Hotspot Shield was used to bypass government censorship during the Arab Spring protests in Egypt, Tunisia, and Libya.
PirateBrowser is an Internet browser by The Pirate Bay used to circumvent Internet censorship.
Lantern is a free and open source internet censorship circumvention tool that operates in some of the most extreme censorship environments, such as China, Iran, and Russia. It was used by millions of Iranians during the Woman, Life, Freedom protests in Iran in 2022 and again during the surge in censorship in Russia following the Russian invasion of the Ukraine. Lantern uses a wide variety of protocols and techniques that obfuscate network traffic and/or co-mingle traffic with protocols censors are reluctant to block, often hiding in protocols such as TLS. It also uses domain fronting. It is not an anonymity tool like Tor.
Domain fronting is a technique for Internet censorship circumvention that uses different domain names in different communication layers of an HTTPS connection to discreetly connect to a different target domain than that which is discernable to third parties monitoring the requests and connections.
Mullvad is a commercial VPN service based in Sweden. Launched in March 2009, Mullvad operates using the WireGuard and OpenVPN protocols. It also supports Shadowsocks as a bridge protocol for censorship circumvention. Mullvad's VPN client software is released under the GPLv3, a free and open-source software license.
A virtual private network (VPN) service provides a proxy server to help users bypass Internet censorship such as geo-blocking and users who want to protect their communications against data profiling or MitM attacks on hostile networks.
Why is this called Snowflake? It utilizes the "ICE" negotiation via WebRTC, and also involves a great abundance of ephemeral and short-lived (and special!) volunteer proxies
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