How to Help
How it Works
How to Use It
Some Technical Information
As of 2017, the flash proxy project is deprecated.
It was deployed in Tor Browser between 2013 and 2016,
but has since been superseded by newer and more effective
If you want to help support a newer circumvention system
designed along the same principles as flash proxy, please see
Flash proxies are a way of providing access to a censorship
circumvention system such as Tor.
A flash proxy is a miniature proxy that runs in a web browser. It checks
for clients that need access, then conveys data between them and a Tor
Tor has bridge
relays, but in some cases even these can be blocked despite the fact
that their addresses are handed out only a few at a time. The purpose of
this project is to create many, generally ephemeral bridge IP addresses,
with the goal of outpacing a censor’s ability to block them. Rather than
increasing the number of bridges at static addresses, we aim to make
existing bridges reachable by a larger and changing pool of addresses.
“Flash proxy” is a name that should make you think “quick” and
“short-lived. ” Our implementation uses standard web technologies:
(In the long-ago past we used Adobe Flash, but do not any longer. )
while you are viewing this page your browser is a potential proxy
available to help censored Internet users.
Copy and paste this HTML into your web site or blog. An example is at
the bottom of this page.
There is an options page (the same page you
get by clicking on the badge) with which users can choose whether they
want to be a proxy. By default, if a user has not made a choice, they
will be a proxy. If you want only people who have explicitly clicked
“yes” to be a proxy, add the cookierequired parameter. If a
user has selected “no, ” they will never be a proxy, regardless of the
presence of cookierequired.
Cupcake is an
always-on flash proxy plugin for Chrome. Click
here to install from the Chrome web store.
Flashproxy Badge is an always-on flash proxy plugin for Firefox.
here to install from Mozilla Add-Ons.
your Wikipedia skin to include a flash proxy badge.
This paper contains a fuller description of the system and the results
of performance experiments.
Evading Censorship with Browser-Based Proxies (PDF)
In the Proceedings of the 12th Privacy Enhancing Technologies Symposium (PETS 2012), LNCS 7384, pp. 239–258, 2012.
An overview of the flash proxy system and its state of development as of
How It Works
In addition to the Tor client and relay, we provide three new pieces.
The Tor client contacts the facilitator to advertise
that it needs a connection. The facilitator is responsible for keeping
tack of clients and proxies, and assigning one to another. The
flash proxy polls the facilitator for client
registrations, then begins a connection to the client when it gets one.
The transport plugins on the client and relay broker
the connection between WebSockets and plain TCP.
A sample session may go like this:
The client starts Tor and the client transport plugin program
(flashproxy-client), and sends a registration
to the facilitator using a secure rendezvous. The client transport plugin
begins listening for a remote connection.
A flash proxy comes online and polls the facilitator.
The facilitator returns a client registration, informing the flash
proxy where to connect.
The proxy makes an outgoing connection to the client, which is
received by the client’s transport plugin.
The proxy makes an outgoing connection to the transport plugin on
the Tor relay. The proxy begins sending and receiving data between the
client and relay.
The whole reason this is necessary is because the client cannot
communicate directly with the relay. (Perhaps the censor has enumerated
all the relays and blocked them by IP address. ) In the above diagram,
there are two arrows that cross the censor boundary; here is why we
think they are justified. The initial connection from the client to the
facilitator (the client registration) is a very low-bandwidth,
write-only communication that ideally may happen only once during a
session. A careful, slow, specialized rendezvous protocol can provide
this initial communication. The connection from the flash proxy to the
client is from an IP address the censor has never seen before. If it is
blocked within a few minutes, that’s fine; it wasn’t expected to run
forever anyway, and there are other proxies lined up and waiting to
Doesn’t the censor win just by blocking the facilitator? Doesn’t this
shift the problem from bridge-blocking to facilitator-blocking? The
short answer to these questions is no. We assume that
the censor has blocked the facilitator. For more details, see the
From the user’s perspective, only a few things change compared to using
normal Tor. The user must run the client transport plugin program and
use a slightly modified Tor configuration file. Complete details are in
Flash proxy is built into Tor Browser.
Follow this link to download Tor Browser.
Tor Browser download page
Next, read the
proxy howto to learn how to configure port forwarding. See the
manual configuration in the rest of this section if the browser bundle
Limitations on outgoing connections
It is a restriction of WebSockets
that they cannot receive TCP connections, only open them.
That is the reason for the client transport plugin: it allows Tor to
receive connections instead of making them.
The badge changes color depending on its state.
Dark blue means the proxy is running but no client is being served.
Light blue means a client is currently being served.
Gray means that the badge has disabled itself. This can be because
it has detected it is running on a mobile device, or the browser doesn’t
support WebSocket (this happens on Internet Explorer 9).
Black means that there was an internal error and the proxy is no
All the programs making up the flash proxy system are free software and
their source code is visible. To get a copy of everything, run this
Or browse the code through
Flash proxies began as a project in Stanford’s
CS294s class in spring 2011.
David Fifield, Nate Hardison, and Jonathan Ellithorpe were members of
the project team. They and Emily Stark, Roger Dingledine, Phil Porras,
and Dan Boneh wrote a research paper on the
subject. Development continues as part of
the Tor Project.
Estimated average number of concurrent users. See the
site for more control over the graph and historical measurements.
David Fifield <>
Research paper (PDF)
Bug reports and open tasks
(including closed tickets)
7 Best Free Proxy Websites to Access Blocked Websites
Blocked websites sometimes are really annoying. Especially if you need to access those blocked websites in your college or workplace. There are several ways to access blocked websites, but the easiest method is to use free proxy websites with a web browser. The best thing about these websites is that they don’t require any particular web browser and you can surf the web at a good speed. Another advantage is being anonymous while surfing the desired sites as proxy websites operate through passing user’s requests via their own servers, thus preventing user’s IP address to show (this allows users to even watch videos that are restricted in a particular region). Most organizations including colleges, universities, banks, etc, prohibit access to several popular websites these days – especially all major social media networking sites. It’s really annoying so, here is our list of the best free proxy websites to access blocked websites that will help you in defeating all common internet restrictions:
KPROXY enables millions of users worldwide to access blocked websites while protecting their privacy. Working since 2005, the website is the most reliable for a secure and safe web proxy browsing experience.
The website also offers a KPROXY agent for free download. It also offers a paid package that allows internet surfing without ads and offers fast servers.
It is a free web proxy for you to surf the web anonymously with a secure connection. The website also offers a PRO version of the software which offers extra benefits like enhanced security and decoding, total prevention of identity, super compatibility, and user-friendly interface.
This Indonesian proxy website is really effective in playing videos and allows flawless web browsing too. The only downside for this site is the annoying ads that pop up every now and then.
ProxFree is simply awesome and totally free and allows access to any blocked website. This proxy site is the best choice for those who are looking to bypass censorship barriers to watch online flash videos.
The interface is really simple and video streaming is really fast (even if you are using it in a very tightly secured network).
It is just another clean and sleek online proxy site for you to access your favorite banned websites. Just type the URL in the given box and you will be redirected to the desired website. This website also offers a free newsletter that gives the latest updates on other popular proxy websites.
Apart from the above mentioned free proxy websites, the following sites can also be very handy when it comes to fooling a restricted network:
Feel free to share with us the proxy sites that you use for accessing restricted sites at your place in the comments section below!
Flash proxy – Wikipedia
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 (amongst others) 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. 
2 See also
4 External links
Free and open-source software portal
Free speech portal
Freedom of information
^ Gallagher, Sean (2014-08-14). “A portable router that conceals your Internet traffic”. Ars Technica. Retrieved 2016-04-10.
^ “Combined flash proxy + pyobfsproxy browser bundles | The Tor Blog”. 2013-02-23. Retrieved 2016-04-10.
^ “Flash Proxies”. Retrieved 2016-04-10.
^ Jones, Martin (2011). “Biting the Hand That Serves You: A Closer Look at Client-Side Flash Proxies for Cross-Domain Requests”. Detection of Intrusions and Malware, and Vulnerability Assessment. Lecture Notes in Computer Science. 6739: 85–103. doi:10. 1007/978-3-642-22424-9_6. ISBN 978-3-642-22423-2.
The primary developer gives an overview at Stanford University
vteInternet censorship circumvention technologiesBackground
Internet censorship in China
Censorship and blocking technologies
IP address blocking
DNS cache poisoning
Great Firewall of China
Blocks on specific websites
PrinciplesWith a proxy server
Without a proxy server
IPv6 transition mechanism
Anti-censorship softwareFree software
Anonymous P2P network
Physical circumvention methods
USB dead drop
Italics indicates that maintenance of the tool has been discontinued. Category Commons