Stephanie gave an overview of threats to net privacy, current methods for protecting privacy and how to stay anonymous while accessing the net or publishing on it.

Most people browse the web, send email or take part in online chats or irc without realizing how easily their data can be accessed by a third party. In order to understand the need for privacy on the net, it’s best to first take a look at how privacy is compromised.

As data travels across the net, many people theoretically could gain access to it. This might happen by tapping the actual lines, (e.g. telecommunication companies, government agencies, in case of cable internet maybe your neighbours), or by (illegally) accessing hosts/routers (e.g. your isps sysadmin, the sysadmins at the isp where the webserver is hosted, the admin of the webserver itself). If you access a webserver, the system operator can easily find out which computer you're coming from and what you're trying to access by reading the logfiles of his or her system. Visiting websites includes special dangers to your privacy, because your browser usually transmits a lot of information to the website, e.g. the URL of the website you come from, the operating system you are running, the name and version of your browser, and sometimes even your name and e-mail address. And some websites even will transfer information to your computer, by so-called cookies, which contain a variable, a value and the name of the website it goes with.
Although most sysadmins won’t touch e-mails, it iswise to protect your material and take some precautions. Tapping a line doesn’t make sense, if data traffic is encrypted. The most common methods include SSL (mainly used to protect webtraffic) and PGP (for e-mail). And the browsers configuration should not give out real name or email address, as well as generating a warning before receiving a cookie.

To send anonymous email it is possible to use different kinds of remailers, which offer different grades of anonymity: Old style remailers simply match your own email address to a pseudonym, and the other way round when you get a reply. Problem: The same server stores all information. If it gets compromised or forced to give out this information, anonymity is gone. Cypherpunks and Mixmaster Remailers work with a chained remailer system. Email is passed along serveral servers and is encrypted several times to ensure that noone knows how to match the real email address to the pseudonym.

Perhaps the most commonly used way to ftp or browse the web anonymously it the use of an anonymizing proxy. This works in a similar way as the simple remailer service who just matches your email to a pseudonym. The anonymizing proxy’S IP and portnumber have to be used as a proxy in the browser. If it gets compromised or the admins are forced to give out information to authorities, anonymity is void.

„Crowds" is a more complex system developed by AT&T, which again works like multiple anon proxies chained together. Drawbacks: things will get very slow, and it does not completely prevent traffic analysis (original server can be located by following traffic through the Crowds net). Yet Onion Routing is a more complex approach to gain anonymity. It also works with a chain of proxies, but also employs 'mixing' as described in the remailer section and encrypts the data (both directions) in a similar way.

PipeNet works in a similar way except that there is constant traffic between the servers. This is to prevent traffic analysis. It has never actually been implemented. And Freedom is a commercial product developed by ZKS in Montreal. It works similar to Onion-Routing, but also includes elements of PipeNet, since it puts additional cover traffic on the line.

Perhaps its not enough to just access content anonymously. In some cases it might be interesting to publish information anonymously. Of course the possibility for abuse is rather high in this case, but, for example should a polical group, risking prosecution, be able to publish their information safely and anonymously? In the future, certain content such as drug information, uncensored news, etc might become illegal. In this case there has to be a possibility to retain free information by protecting the authors.

Janus is a very simple system to provide anonymity for webauthors. It works similary to an anonymous webproxy, just the other way around. Janus provides an encrypted url which can be published. If this url is typed in a browser, Janus translates the request and retrieves the real webpage. Drawback: All security lies in the Janus server.If it get compromised or the admins get forced by an authority to surrender their data, the webpage is no longer anonymous. Another danger is that search engines index almost everything, some of them don't even pay attention to a robots.txt, telling them not to index. If there's any other link to this site it will probably get indexed, so that once the page has been retrieved via Janus the orignal url could be found with the help of a search engine.

The Rewebber Network is another chained form of proxies, similar to the remailer network. The advantage of this is that there is no single point of failure anymore. In order to access a webpage via the Rewebber Network long urls need to be specified, since there are multiple layers of encryption. And TAZ (Temporary Anonymous Zone) acts as some form of information server which provides the long encrypted url via a shorted identifier.

For more detailed information about the ideas mentioned follow the links given in the complete documentation which is linked from the obn-website. (http://www.r4k.net/cyfem/)