* Unmodified copies of this document may be freely
This web page is intended to be a very basic
introduction to Internet security and privacy issues for activists and
citizens. It is not meant to be an exhaustive text of all the
issues, nor does it deal with any of the issues in great depth. My
intention is not to teach the theoretical or technical basis for
security on the Internet, but rather to enable the user to protect
his/her security and privacy as quickly and easily as possible.
Before we begin, we need to clarify the terms that we
will be using in this essay.
'Anonymity': refers to the ability to engage in
activity on the Internet, such as emailing, surfing, or posting to
newsgroups, in such a manner that no one can determine who you are or
practically any other nontrivial information about you.
'Privacy': refers to the ability to store
information, or transmit information, from sender to recipient(s) in
such a manner that only the intended recipients or owner(s) are able to
decode, read, or use the information. This usually involves making sure
that no unintended third-party is able to intercept the information
along the transmission route and make any real use of it. In the
context of websurfing, I will also use the term 'Securely'.
'Encryption': refers to the process in which data
is 'scrambled' in such a way as to make it deliberately unintelligible
to anyone who reads or gains access to it other than the intended
Every computer on the Internet has an IP address. This
is a number of the format x.x.x.x (where each x is a number from 0-255)
which uniquely identifies your computer on the Net. This number is
essential for sending and receiving information from one computer on
the Net to the next. If you are on a dial-up connection, this number
usually changes each time you connect. Alternatively, your IP address
may not change if you are on a high-speed, always on line, or your
Internet Service Provider (ISP) has designated you a 'static' IP
What this means is that your Internet activity can
potentially be recorded or traced, either by your ISP or by the various
servers (computers) that you connect to. Web-sites, for example, are
known to sometimes log IP addresses. What further information about you
that can be obtained with the knowledge of your IP address varies
greatly depending how you are connected to the Net. Suffice to say your
ISP keeps a log of who is using what IP address at what times. If
someone should complain to your ISP for whatever reason about activity
from such-and-such IP address, or if the authorities legally force your
ISP to tell them who was using what IP address at whatever time, then any
such activity can be traced directly back to you.
Why should I
hide my IP address?
Because of the way that your IP address is a unique
identifier for who you are and your activity on the net, it is
essential that you hide your IP address while surfing the web and doing
other net activity if you wish to preserve your anonymity and preserve
The simplest way to do this is to use a 'proxy'. Simply
put, a proxy is an intermediary machine between you and the computer
that you wish to connect to. The way a proxy works is this: If you wish
to access a file on another computer on the net (machine X, say), you
tell the proxy machine to get it for you. The proxy machine then
retrieves the information from that machine and then passes it on to
you. Machine X knows nothing about your computer. All it knows is that
the proxy machine made the request for this information. Ideally, any
information that it gathers will be about the proxy machine, and not
Next, we will discuss how to hide your IP address while
surfing and web-mailing by setting up your browser to use a proxy. This
will also be useful for sending anonymous web-based mail, as we shall
see later on. Anonymous emailing will also be dealt with in more depth
How do I hide my
Setting up a proxy on your browser may sound
complicated, but it is actually a fairly simple process. All browsers
that I am aware of have a feature which allow you to configure them to
First, find an anonymous proxy to use by
visiting one of these pages:
Both pages have instructions on how to configure your
browser to use Proxies. I will not go into detail here on how to do it,
since I believe these pages explain them quite nicely and better than I
ever could. The Multiproxy site contains a program called 'Multiproxy'
which installs on your computer and which, once configured, makes your
browser 'chain' a large number of proxies together, providing the
assurance of maximum anonymity- since there is nothing stopping a proxy
itself from recording your IP address. You do not have to install this
program, however, and can simply use one of the proxies listed with
your browser in the normal manner, as instructed at 'proxys4all'.
The instruction page on the 'Multiproxy' website is here.
The instruction page on the 'proxys4all' website is here.
that your IP address is hidden
Once you have configured your browser to use a proxy, it
is crucial that you check that your IP address is hidden and you are
indeed anonymous; you may have misconfigured your browser, the proxy
you installed may not have been anonymous, or a number of other
problems may have occurred.
To do this, you need to use what is called an
'Environment checker'. This is normally a web-page that you visit that
tries to gather as much information about you that it can. The most
important piece of information being, of course, your IP address. From
this web page, you can tell how much information you are giving away
while browsing. It is recommended that you first visit such a web page
with your proxy turned off so you can determine your IP address if you
don't already know how to obtain it. Once you have done that, revisit
the 'Env checker' web page (or a different one) and compare the two
results. The 'Env checker' web page should now show the IP address of
the proxy that you have configured - or, if you have chained several
proxies, the last proxy in the chain.
Here is a very
good 'Env checker' at http://www.privacy.net/
Both the 'Multiproxy' and 'proxys4all' websites also
have 'Env checkers' or links to them.
|Your Internet Service
of ISP surveillance
It is important to be aware that everything that you do
online can be monitored and recorded by your ISP- every web page your
visit, everything you type and send over the Internet, everything you
download. Most of the techniques outlined in this document concentrate
of preventing 'third-parties' from being able to trace particular
Internet activity back to you or your Internet Service Provider.
However, if the authorities already suspect that you are
engaging in 'suspicious' activities (for example, organising a peaceful
protest), they can order your ISP to start recording your activities
(although unlikely, they may already do so as a matter of course for
all users) and hand over these records to them.
It is worth briefly mentioning that government spy
networks such as Echelon
pose a similar threat to your privacy and anonymity by intercepting
data en route. This need not involve your ISP at all.
A solution to the
The only way to prevent this sort of monitoring is to
make sure that everything that you send out to and receive over the Net
is encrypted. This includes surfing, emailing and newsgroup posting.
Simply put, encryption means 'scrambling' or 'encoding' your data so
that no one but the intended recipients can make any sense of it if
they intercept it along the way or at the destination.
Below we will discuss ways of allowing you to do the
main three Internet activities - Web Surfing, Emailing, and Newsgroup
posting - anonymously, and if you wish, using encryption for
extra security. We will also discuss how to send email securely
so that only the intended recipients can read it, whether the sender is
anonymous or a known party.
If you have configured your browser to use a proxy or
proxies correctly, then you are already surfing anonymously. The web
site that you visit will almost certainly not be able to trace your
visit back to your computer. The more proxies you have chained, the
lower this probability.
Another way of surfing anonymously without configuring
your browser to use a proxy, is to use a 'CGI' web-based proxy. This
just means a web site which you can visit as you would any other web
site, but that which you can make page requests to, and will act as an
intermediary or proxy server for you. This is no doubt the easiest
method of anonymous surfing. Here are a few good web based proxies:
Anonymizer.com - http://www.anonymizer.com/
Janus Rewebber - http://www.rewebber.de/
Anonymouse - http://anonymouse.is4u.de/
Safeweb - http://www.safeweb.com/
Autistici.org - https://proxy1.autistici.org/
The last two of these - 'Safeweb' and 'Autistici.org' -
also encrypt all the URL's that your request and all
the data that leaves or enters your computer. This allows you to browse
the web securely.
[*] You should be aware that the trustworthiness of
safeweb has been called into question for not entirely unjustified
reasons, which can be read here,
web based remailers
Anonymous emailing can be very easily achieved through
the same method as anonymous surfing. There are web sites that provide
you with an email template which you fill out in the same way as a
regular email message when using a POP/SMTP account (for example, when
you use a mail client such as Eudora, Pegasus or Outlook Express).
These web sites then forward your mail to the destination you designate
in the 'To:' and 'CC:' fields. The mail could then be theoretically
traced back to the web remailer that you used, but not to you or your
computer. Such a service is called a 'web to mail gateway'. Here are a
few good web based anonymous remailers:
(a) Anonymouse - http://anonymouse.is4u.de/
(b) The Global Internet Liberty Campaign remailer - http://www.gilc.org/speech/anonymous/remailer.html
(c) Riot anonymous emailer - https://riot.eu.org/cgi/remailer.cgi
These three remailers are listed in increasing level of
security. The 'Anonymouse' remailer (a) does not encrypt your
message as it is sent from your computer to the server and does not
chain your message with other anonymous remailers. The GILC (b)
remailer chains several anonymous remailers together, thereby enhancing
your security greatly, but is also not encrypted. The person
you email may not be able to determine who you are, but anyone snooping
in on your communications will be able to determine the contents of
your email, who you emailed, and at precisely what time. The Riot (c)
anonymous remailer provides the highest level of security. It chains
several remailers together, like the GILC remailer, but also uses 'SSL'
encryption to scramble your data during transmission from your computer
to the server.
Anonymous remailers that use encryption are both anonymous
Use whatever level of security that you think best fits
your needs. Always be aware of the type of security whatever remailer
you are using provides in terms of chaining, encryption, and whether or
not you can trust the provider of the service itself.
Hushmail is a
free webmail service that offers anonymous and secure
communications to its users. The advantage of having a webmail account
over using an anonymous web remailer is that people can reply back to
the messages that you send out, giving you a two-way communication
channel. If the service that you use does not require you to provide
your name and other personal information, like Hushmail, or the
information tht your provide is false, then it can be considered somewhat
anonymous. I stress the word 'somewhat',
because the webmail service provider can still determine your IP
address in the usual manner unless you have taken steps to conceal it -
as I have explained above.
Apart from anonymity, Hushmail provides a secure channel
by which Hushmail users can send emails to each other. In other words,
Hushmail users can send emails to each other without fear that their
messages are being intercepted en route and being read by an
unintended third-party. Once again this is achieved through encryption.
This encryption process is done completely automatically and the users
sending and receiving mails don't have to do anything differently than
if they were using regular webmail accounts.
You must be remember, though, the privacy aspect of
Hushmail only works when sending messages between Hushmail
accounts. If a Hushmail user sends a message to anyone other
than another Hushmail user, then the communication will not be
secure, though if they have taken the adequate
steps, they will be remain anonymous. Also remember that all your
emails are still being stored on Hushmail's mail servers and the
authorities can always force Hushmail to hand over the contents of your
Hushmail is useful as a quick and easy way to send
secure messages between you and your friends or fellow activists that
requires no additional computer expertise above sending a regular email
message. It is highly recommended.
 The author of this article is not encouraging any
illegal activity such as falsifying information. Every user is
responsible for their own online activity.
PGP (Pretty Good Privacy)
PGP, or Pretty Good Privacy, is a software program that
provides practically unbreakable encryption for anyone with a
reasonably powerful computer to use for all their online
communications, including and especially email, as well as a way of
securing files on their computer from prying eyes.
Unlike when using Hushmail, data is encrypted by the
user himself using the PGP program and the user can verify this fact
for himself by examining the data. Also, when using PGP, there is no
intermediary location that stores emails or files in their unencrypted
form. For these reasons, among others, PGP provides probably the best
security a home PC user can get. In fact, the level of security is so
high that, when used properly, not even government agencies with huge
computing power at their disposal are able to crack a high level
security (large keylength) PGP encrypted file. It is for this fact that
the US government classified PGP software as 'munitions', and until
very recently, 'banned' it from being exported from the United States.
Apart from encryption, another feature of PGP, is the
implementation of 'digital signatures'. Briefly, this means that one
can digitally 'sign' a document in such a way that the intended
recipient is absolutely sure that the source is authentic, and that the
message or file has not been tampered en route.
PGP is widely available over the internet. For starters,
you can go to C|NET - download.com
and type in 'PGP' in the search text box after choosing your operating
system. For beginners, it is recommended that download 'PGP Freeware'
instead of 'PGP x.x.x'.
Be forewarned, although the authors of the software have
tried to make the software as easy to use as possible, some users may
experience difficulties in getting the software to work. Although
somewhat confusing to operate at first, the rewards are well worth the
effort. Therefore, I strongly recommend that every computer user above
novice level who is concerned about their online privacy, make a
concerted attempt to install and run PGP on their home machines.
 It is a tenet of cryptography that nothing
can or should be considered unbreakable under all circumstances, all of
the time, for all time. However, the cryptographic methods of PGP are
soo strong that, when used properly, they are considered to be
unbreakable - practically speaking - for the time being and
Anonymous newsgroup posting can be achieved most easily
through the same method as anonymous emailing... that is, through a web
interface. Such a service is called a 'web to news gateway'.
and 'Riot', as
listed above provide web to news gateways.
In addition to the above two, here is an additional
Elandnews 'Pseudo anonymous web2news' - http://www.elandnews.com/mauritius/anon.html
Another way of sending anonymous newsgroup messages is
to sign up to 'Google Groups',
which is a service provided by Google which provides a near complete
inferface to newsgroups via the web; users can both read and post
In order to access this service, you need a valid email
address, but no other information is asked of you other than the
username that will appear on your posts - which can be any name of your
choice that is not already taken.
Of these four, only the 'Riot' gateway is anonymous,
chained and secure. Remember to always use a proxy when
connecting to any of these web to mail or web to news services if you
want to ensure your anonymity.
This essay has, up until now, discussed security and
anonymity when a user is transmitting information over the internet.
There is, however, another important aspect which we have not discussed
- the security and privacy of the files stored on your computer,
including files containing records of your internet activity. It is in
this section that we will briefly discuss a few of the most important
areas in this subject.
Many users do not realise the size and scope of the
trail of information that they leave on their computer when they open
files and browse the internet. A great deal of what you do online and
offline on your computer is being recorded on various files on your
For example, every URL (hypertext link) that a user
visits is recorded on his or her hard drive. This information can be
stored for months, years, or even an indefinate amount of time. Every
image, or almost every image, that has been loaded while browsing the
web is also stored on the hard drive for a specified period of time, or
until the cumulative space consumed by these images reaches a certain
amount. In addition, URL's are sometimes stored in a browsers 'Location
bar' for easy access later on. These things are done (ostensibly) in
order to speed up and facilitate a users 'browsing experience', but
obviously raise seriously privacy concerns.
Another concern is the use of 'cookies'. These are small
text files that are created on your computer when you visit a web-site
that keep track of your online activity within the site that the cookie
originated from (sharing cookies is rare, but does happen on
occassion). A cookie is sometimes used, for example, to determine
whether a user has visited the site before, and if so, what areas they
took an interest in.
There are four main areas that a user should primarily
be concerned with with regards to surfing habits:
- The History folder, located at c:\windows\history
- ...which stores URL's of every page you have
- The Windows Temp folder, located at c:\windows\temp
- ...which stores .html and image files from pages
you have visited
- The Cookies folder, located at c:\windows\cookies
- ...which stores all the cookies you were given by
- The Temporary Internet Files folder, located at
- ...which again stores the URL's of the pages you
have visited, along with some other information.
in addition to the 'normal' files which are stored in
these folders, an addition special file is also added. This file is
called 'index.dat' and cannot be deleted from within Windows.
This is potentially a very big problem, because it also contains
information of a sensitive nature (for example, URL's).
You can solve this problem by exiting to DOS (completely
quitting Windows, not just opening up a DOS window) and deleting these
folders by hand or by modifying your 'autoexec.bat' file to do this for
your every time you start up your computer. I would recommend the
latter, as the index.dat files will be recreated by Windows anyway and
it wont be long before they start to grow in size again by accumulating
more and more sensitive data; if you modify your 'autoexec.bat' file to
delete these files for you, you will never have to worry about them
Find the text file called 'autoexec.bat' in your root
directory (usually C:\). If you can't find it, that's ok, just create a
new one. Copy the below five lines in italics into it and save. If you
want to actually see the process happening every time you start up,
ommit '@ECHO OFF' entirely and the '> NUL' part at the end of each
DELTREE /y c:\windows\history\*.* > NUL
DELTREE /y c:\windows\tempor~1\*.* > NUL
DELTREE /y c:\windows\temp\*.* > NUL
DELTREE /y c:\windows\cookies\*.* > NUL
Deleted files not
When you 'delete' a file using right-click, 'Delete' in
Windows or typing in 'del' from DOS, you are not actually erasing that
information from your hard drive. What you are instead doing is
removing all references to that information. Your operating
system does this because it is a lot quicker to remove references to
files and file information than to physically write over or delete
(destroy) the actual information stored on the disk.
This can present problems for privacy, since information
which you may have thought you safely deleted can actually later be
retrieved by someone who you may not wish to have access to it.
Remeber, this also holds true for the files listed in
the above section relating to your browser history, temp, and cookie
The solution is to download a program which will both a)
delete individual files for you in such a manner as to completely
(irretrievibly) destroy them by overwriting on top of file data several
times and b) perform a 'wipe free disk space' operation that will do
the same thing on the free space on your HD (which may contain file
fragments of old files erased 'normally').
There are several of these programs, called 'file
wipers', at C|NET - download.com.
Among some of the better ones are 'Eraser' and 'BCWipe'. Go to C|NET
and do a file search for 'file wipe', or type in the names in the
search box of the above two programs directly. I would recommend trying
out a few to see which one you think is the fastest and most productive.
Don't forget to wipe both sensitive individual files and
free disk space (on a regular basis).
The only way to keep your files private with any real
degree of security is to encrypt them on your hard disk. While
there are many utilities that do various tricks with your operating
system to hide or password protect your files, ultimately these should
only be used in conjunction with 'strong' encryption to
provide additional security.
There are many programs available to do this. Again, you
can find a number of them on C|Net. While there are many programs that
provide encryption, what is needed is 'unbreakable' encryption. While no
encryption technique is fool-proof and will remain so
forever, there are encryption techniques which, for all
intents-and-purposes (if used correctly) are, practically-speaking,
unbreakable (as far as we know) for the time being.
PGP is one program which provides such encryption
techniques. Though are other programs out there besides PGP, but PGP is
certainly the most well-known and trusted. Therefore, I recommend using
PGP for this purpose, in addition to encrypting emails.
Be sure to read the manual first and use PGP properly. I
would also recommend a key size of at least 2048 bits - you will
understand the meaning of this once you download the program and read
I will briefly now only mention three future
communication technologies for the internet that may be of interests to
activists and citizens concerned about their privacy.
The three programs are called 'Freenet', 'Peekabooty' and 'psst'. There are
working versions of these programs at this very moment available for
download, but users should be aware that they are still under
program that implements a peer-to-peer network over the internet. I
will not go detail as to what this means, other than to say that
peer-to-peer networks are computer networks that have a decentralised
structure- making them less vulnerable to attack and censorship.
allows you to share files and information using your web browser in a
way that is private (nobody knows what you're downloading or
uploading), anonymous, and uncensorable. For these reasons Freenet has
the potential to be an extremely useful technology in the
context of modern 'information warfare'.
Not much is known about Peekabooty, as no versions have
even been released yet. I mention it here because it sounds quite
promising. Like Freenet, Peekabooty will allow users to download
content anonymously. Unlike Freenet however, Peekabooty will not grab
this content from it's own network, but instead uses the web. So for
all intents-and-purposes, it will be an anonymous browser.
In similarity with Freenet, Peekabooty is being designed
specifically to the censoring of content by governments and
corporations very difficult.
If you would like to learn more about Peekabooty, the
best thing to do is to do a Google seach for 'Peekabooty', or simply
link to do so automatically.
is a chat program that runs on both Windows and Linux and which the
programmer describes as:'Simple, free, convenient no-frills Instant
Messaging software with strong encryption...'
Alternatively, you can get the PGP plug-in for ICQ if
you are more comfortable with it. psst has the advantage of being very
small and quick and won't add any other files to your system.
I hope this document has been informative and useful. It
covers the very basics of Internet security which everyone should
understand if they are concerned about their online privacy and wish to
do something about it. I have not mentioned Firewalls, Trojan Horses,
and Viruses. These topics may be covered in the next version of this
document. Knowledge of them will greatly enhance the chances of you
maintaining your privacy. I therefore encourage readers of this
document to investigate these matters on their own by clicking on the
These links concern the topics mentioned immediately
above as well as other issues. They are written for varying levels of
CERT Manual on
Home Network Security
Focus's basic Basic Security Checklist for Home and Office Users
and finally the wealth of information at Astalavista.com