Patrick’s development blog

become anonymous on the internet using Tor

Posted in Articles, Security by Patrick on July 23, 2008

Tor is a platform independent program that protects you from traffic analysis. Traffic analysis is a form of surveillance of your network traffic which is a threat to your personal integrity. Tor is usually used to surf anonymously, but can also be used with for example instant-messaging applications.

How Tor works
When using Tor, your communication with the internet is protected by distributing it trough a network of different relays trough the world which are run by volunteers. The communication is also encrypted so no one can see what you’re doing or learn your location.

I recommend using the Firefox add-on Torbutton which provides an easy way to disable/enable Tor in Firefox. This way, you don’t have to configure your browser either.

Pitfalls with Tor
Watch out for cookies, flash files, java applets and similiar web applications. They can reveal your IP-address even if you use Tor. Using Add-ons for Mozilla Firefox like No Script and Flash Block can prevent this. Be sure that you don’t fall for things like this.

Even if Tor encrypts your traffic inside the Tor-network and makes you anonymous. The last relay you are connected to, which is directly communication with the webserver can still see your traffic. Don’t use Tor if you do things that can expose your identity, for example logging in to your webmail (if you truly want to be anonymous that is). Using an encrypted protocol like HTTPS prevents this though.

Read more about potential pitfalls here: http://www.torproject.org/download.html.en#Warning

To sum it up
If you want to surf anonymously, this is a very useful program as it also hides your IP-address. But remember that web apps like Flash can still expose your IP. A lot of people believes that installing Tor will automagically make them anonymous. That’s wrong however. You have to configure the application correctly you want to use with Tor. If you’re using Firefox, the Torbutton add-on makes this automatically.

A good idea might be to install a portable browser which you use only when you want to be anonymous. Configure this browser so it doesn’t accept cookies and install a flash blocker, block java and other “media” that could expose your IP-address. It’s recommended to only use services like webmail if the site uses SSL or another secure connection.

There is a portable version of Firefox called Firefoxportable.
Tor’s official website: http://www.torproject.org/

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Recover lost partitions with Testdisk

Posted in Linux/GNU by Patrick on July 21, 2008

By mistake, I deleted some of my partitions and totally messed up my partition table a couple of days ago, removing the possibility of booting up my computer at all.  Luckily, I found a open source program called Testdisk.

Testdisk is a free data recovery software that can recover lost partitions and make partitions bootable again. Here’s how I recovered my Windows XP partition using a Ubuntu live-CD.

First, I enabled all uncommented repositories in /etc/apt/sources.list.

sudo su
nano /etc/apt/sources.list

Then I updated the package repository list and installed Testdisk:

apt-get update
apt-get install testdisk

When it’s installed, you can start it by typing its name in the terminal. You’ll be asked to create a log file (optional). After that, choose analyze and Intel/PC partition. Your partition table will be shown, wait until it’s analyzed. After the analyze is done, you can also choose to make a deep scan which is recommended. If you decide to recover a partition, just click the right arrow button so the current selection turns green and continue by pressing Enter. You’ll be asked to write this partition on the partition table. Do this.

That’s all, that worked for me at least. I only have some weird problems with my boot manager right now, but the partition is fully bootable.