Illuminated CCC logo in front of the bcc @ 26C3
Archive for the ‘Tech’ Category
GSM Encryption (or the Lack Thereof)
Thursday, December 31st, 2009
At 26C3 there were a couple of pretty interesting talks dealing with GSM security and how it can be easily broken through active (IMSI catching) and passive (rainbow table attacks on the A5/1 cipher) attacks.
Now, researcher’s are pushing to phase out GSM’s A5/1 cipher replacing it with modern, non-proprietary cryptography as countermeasure to the weaknesses facilitating A5/1′s susceptibility to passive eavesdropping. While this is certainly not a bad idea, it will end up with all but secure GSM calls considering that for GSM calls only the wireless interface benefits from the encryption. It will prevent John Doe from listening to your GSM calls using a wiretapping device placed in front of your apartment, but by no means will it lead to end-to-end security for GSM calls.
So, instead of attacking the wireless interface a malicious hacker would have to turn to the (fixed) telephone network to get hold of your calls.
In the end, only end-to-end encryption of calls will be able to prevent such attacks, so this is IMHO what we should be striving for in the long run.
Running Asterisk on a FRITZ!Box 7270
Sunday, December 20th, 2009
Around a week ago I started experimenting with running Asterisk on my FRITZ!Box 7270 to replace my DECT phone, which has been getting a bit long in the tooth, with a SIP client running on my new Motorola Milestone HTC Desire cell phone so that when I am at home and my cell phone is signed in to my WLAN I can use it as a mobile handset for calls arriving on my landline.
As it turned out it is a little bit tricky to get Asterisk to compile for the FRITZ!Box, so this posting is supposed to summarize the steps I had to take and also comes with a neat helper script, which should automate most of the required preparation and compilation steps.
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Ext4 Performance Improvements
Tuesday, November 24th, 2009
In order to speed up the general performance of my personal computer I put an Intel X25-M SSD into it some time ago and made sure that most binaries that are needed to start up Linux are loaded from the SSD. I could not go without a conventional hard disk, though, because the storage capacity of typical SSDs (or the budget that I am willing to spend) is still too limited. While boot times already improved dramatically after adding the SSD, mounting the file systems located on my conventional hard disk was still limiting the overall speed of the boot process.
That was when I read about the performance improvements introduced by the ext4 file system. (more…)
Sparse File Support for rsync
Tuesday, November 24th, 2009
From time to time one needs to migrate large amounts of data from one file system to another, such as when migrating to a new hard disk, setting up a RAID array or migrating a file system from ext3 to ext4. Each time this happens I find myself googling for the exact rsync command to do the sync operation and each time the command line parameters mentioned in most search results neglect the existence of sparse files. So, mostly as a note to myself, here is the rsync command line I tend to use when replicating data to a new file system (including sparse file support):
rsync -aqxPSH source destination
Garmin Oregon 300 Firmware 3.30
Saturday, November 21st, 2009
In a previous post I outlined how to apply a firmware update for the Garmin Oregon series under Linux without the use of Garmin’s proprietary web updater. In the meantime, Garmin has released a new firmware revision, version 3.30, so if you’d like to update your device to that new version, just grab the .gcd file and follow the instructions in my previous post.
Der technische Fortschritt
Wednesday, October 21st, 2009
Endlich hat man mal einen klaren Vorteil durch seine Technologieaffinität: Möbel Kamprad hat seit meinem letzten Besuch SB-Kassen eingeführt. Ergebnis: Die regulären Kassen vereinigen den Großteil der zahlwilligen Kundschaft in langen Schlangen auf sich, während man an den reichlich vorhandenen SB-Kassen gerade mal eine halbe Minute warten muss. Besonders intuitiv sind diese dann zwar nicht zu bedienen, aber was soll’s. Sonst kommen vielleicht noch andere Kunden auf die Idee, diese zu nutzen. 
Garmin Oregon 300 Firmware Update Under Linux
Sunday, September 20th, 2009
During the recent beta period Garmin regularly released its beta Oregon firmware in a format that could be easily downloaded and installed on the Oregon by unzipping it copying it to the unit when connected as a mass storage device. Unfortunately, Garmin changed this policy again after the beta phase ended, the official firmware only being available through their proprietary (Windows-based) WebUpdater.
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Thank You, MSI…
Sunday, August 16th, 2009
…for using crappy capacitors for the CPU voltage stabilization on my (now former) MSI P965 Neo2 v2 mainboard. This cost me a couple of hours of error-analysis plus ~ 80 EUR for a new mainboard (as I can’t just wait a couple of weeks for the repair of the RMA’d one)…
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The Answer Has Arrived: KDE 4.2 Has Been Released
Thursday, January 29th, 2009
The (at least by me) long-awaited KDE 4.2 release has hit the road! What can I say: It’s beautiful and now contains most of the features that one wanted from a modern desktop environment that were still missing in KDE 4.1. I think I will write a more-detailed article about KDE 4.2 in a couple of days and so will concentrate today on a feature that many people were missing in previous 4.x releases: Icons on the desktop. Yes, there were some workarounds in 4.1.x like placing a large folder view plasmoid on the desktop, but nobody really liked it. In 4.2 the whole desktop becomes a large folder view at the user’s command just as one is used to from KDE 3.5 or Windows. To activate it, just right click on the new shiny desktop and select Appearance Settings from the context menu. Select “Folder View” from the “Type” drop-down and you are done.
