Search Results: "Birger Schacht"

3 January 2022

Birger Schacht: Introducing carl

For some time now I wanted to learn Rust, but I either didn t have the time or couldn t come up with a nice beginner project. Given that I recently found myself to be without a job and we had another lockdown in the part of the world I happen to live in, I decided to give that idea another go (no pun intended). There is apparently a trend to reimplement existing Unix tools in Rust (see exa, a modern replacement for ls , delta, a syntax highlighting pager for git, diff and grep output, bat, a cat clone with wings , zellij, a terminal workspace, ripgrep, a line-oriented search tool ). I looked around what else was out there, but what I wasn t able to find was an implementation of cal(1) in Rust (maybe I wasn t looking hard enough, feel free to point anything out to me I might have overlooked). No cal in Rust even though a calendar implementation would provide the potential to go over the top with terminal colors, which is also very important when writing reimplementations of older CLI tools! So I started writing and soon had a simple prototype of a cal reimplementation. A couple of weeks later I can now present carl, a cal implementation in Rust: default carl output The default output of carl is what you would expect from a commandline calendar tool. It prints the days of the current month and highlights the current day. Other than the cal tools I tried, carl by default also prints days that are in the past in grey. Like cal it can also print three month if you use the -3 switch or the whole year if you use the -y switch.

Colors You can use a theme file to change the colors carl uses for various dates. The name of the theme is set in carls configuration file (in XDG_CONFIG_HOME/.carl/config.toml or system-wide in XDG_CONFIG_DIRS/.carl/config.toml) using the theme setting - carl looks for the theme in the file $ themename .theme in the configuration folders. A custom theme could for example look like this: custom carl output You can change the foreground color, background color and/or style of a date using a combination of various stylenames like BGRed, Bold and FGCyan. The README lists all possible stylenames. A list of date properties defines which dates the specific style should affect- date properties are for example CurrentDate, AfterCurrentDate or FirstDayOfMonth. Again, the README lists the existing date properties and I m happy to implement more of them, if you have ideas.

Ical support I also added the option to list .ical files in the configuration file. carl can display the dates from the ical file(s) with a separate style. There can either be a global style for all the dates from all the ical files by using the IsEvent date property or a separate style for the dates of a specific *.ical file. carl output with ical files Using the --agenda commandline switch carl also shows an agenda of dates from the ical files.

Installation I have uploaded carl to, so you can install carl using cargo: cargo install carl. I also plan to upload it to Debian at some point. If you find bugs or have feature requests, please don t hesitate to create issues.

15 May 2021

Sean Whitton: pinebookpro

I recently bought a Pinebook Pro. This was mainly out of general interest, but also because I wanted to have a spare portable computer. When I was recently having some difficulty with my laptop not charging, I realised that I am dependent on having access to Emacs, notmuch.el and my usual git repositories in the way that most people are dependent on their smartphones all the info I need to get things done is in there, and it s very disabling not to have it. So, good to have a spare. I decided to get the machine running the hard way, and have been working to add a facility to install the device-specific bootloader to Consfigurator. It has been good to learn about how ARM machines boot. The only really hard part turned out to be coming up with the right abstractions within Consfigurator, thanks to the hard work of the Debian U-Boot maintainers. This left me with a chroot and a corresponding disk image, properly partitioned and with the bootloader installed. It was only then that the difficulties began: getting a kernel and initrd combination which can output to the Pinebook Pro s screen and take input from its keyboard is not really straightforward yet, but that s required for inputting disk encryption passwords, which are required on portable devices. I don t have the right hardware to make a serial connection to the machine, so all this took a lot of trial and error. I ve ended up using Manjaro s patched upstream kernel build for now, because that compiles in the right drivers, and debugging an initrd without a serial connection is far too inefficient. What I keep having to remind myself is that this device isn t really a laptop in the usual sense it s a single board computer that s powering several pieces of hardware which together roughly constitute a laptop. I think something which epitomises this is how the power light doesn t come on when you hit the power button, but only when the bootloader or operating system kernel thinks to turn on the LED. You start up this SBC and it loads up some software and then once it has got itself going several seconds later that software starts turning on the screen, keyboard, power LEDs etc. Whereas on an ordinary laptop it s more than you turn on the keyboard, screen, power LEDs etc. all at once, and then /they/ go off and load some software. Of course this description is nothing like what s actually going on, but it s my attempt to capture how it feels as a user, who is installing operating systems, but otherwise treating the laptop s hardware, including things like boot ROMs, as a black box. There are tangible differences between what it is like to do that with an ordinary laptop and with the Pinebook Pro. Thanks to Vagrant Cascadian for all the work on U-Boot in Debian and for help on IRC, Cyril Brulebois for help with crossbuilding, and Birger Schacht for a useful blog post.

23 October 2020

Birger Schacht: An Analysis of 5 Million OpenPGP Keys

In July I finished my Bachelor s Degree in IT Security at the University of Applied Sciences in St. Poelten. During the studies I did some elective courses, one of which was about Data Analysis using Python, Pandas and Jupyter Notebooks. I found it very interesting to do calculations on different data sets and to visualize them. Towards the end of the Bachelor I had to find a topic for my Bachelor Thesis and as a long time user of OpenPGP I thought it would be interesting to do an analysis of the collection of OpenPGP keys that are available on the keyservers of the SKS keyserver network. So in June 2019 I fetched a copy of one of the key dumps of the one of the keyservers (some keyserver publish these copies of their key database so people who want to join the SKS keyserver network can do an initial import). At that time the copy of the key database contained 5,499,675 keys and was around 12GB. Using the hockeypuck keyserver software I imported the keys into an PostgreSQL database. Hockeypuck uses a table called keys to store the keys and in there the column doc stores the OpenPGP keys in JSON format (always with a data field containing the original unparsed data). For the thesis I split the analysis in three parts, first looking at the Public Key packets, then analysing the User ID packets and finally studying the Signature Packets. To analyse the respective packets I used SQL to export the data to CSV files and then used the pandas read_csv method to create a dataframe of the values. In a couple of cases I did some parsing before converting to a DataFrame to make the analysis step faster. The parsing was done using the pgpdump python library. Together with my advisor I decided to submit the thesis for a journal, so we revised and compressed the whole paper and the outcome was now

PUBLISHED in the Journal of Wireless Mobile Networks, Ubiquitous Computing, and Dependable Applications (JoWUA). I think the work gives some valuable insight in the development of the use of OpenPGP in the last 30 years. Looking at the public key packets we were able to compare the different public key algorithms and for example visualize how DSA was the most used algorithm until around 2010 when it was replaced by RSA. When looking at the less used algorithms a trend towards ECC based crytography is visible. What we also noticed was an increase of RSA keys with algorithm ID 3 (RSA Sign-Only), which are deprecated. When we took a deeper look at those keys we realized that most of those keys used a specific User ID string in the User ID packets which allowed us to attribute those keys to two software projects both using the Bouncy Castle Java Cryptographic API (resp. the Spongy Castle version for Android). We also stumbled over a tutorial on how to create RSA keys with Bouncycastle which also describes how to create RSA keys with code that produces RSA Sign-Only keys. In one of those projects, this was then fixed. By looking at the User ID packets we did some statistics about the most used email providers used by OpenPGP users. One domain stood out, because it is not the domain of an email provider: is a domain used in around 45,000 keys. Tellfinder is a Big Data analysis software and the UID of all but two of those keys is TellFinder Page Archiver- Signing Key <>. We also looked at the comments used in OpenPGP User ID fields. In 2013 Daniel Kahn Gillmor published a blog post titled OpenPGP User ID Comments considered harmful in which he pointed out that most of the comments in the User ID field of OpenPGP keys are duplicating information that is already present somewhere in the User ID or the key itself. In our dataset 3,133 comments were exactly the same as the name, 3,346 were the same as the domain and 18,246 comments were similar to the local part of the email address Last but not least we looked at the signature subpackets and the development of some of the preferences (Preferred Symmetric Algorithm, Preferred Hash Algorithm) that are being published using signature packets. Analysing this huge dataset of cryptographic keys of the last 20 to 30 years was very interesting and I learned a lot about the history of PGP resp. OpenPGP and the evolution of cryptography overall. I think it would be interesting to look at even more properties of OpenPGP keys and I also think it would be valuable for the OpenPGP ecosystem if these kinds analysis could be done regularly. An approach like Tor Metrics could lead to interesting findings and could also help to back decisions regarding future developments of the OpenPGP standard.

21 July 2020

Bits from Debian: New Debian Developers and Maintainers (May and June 2020)

The following contributors got their Debian Developer accounts in the last two months: The following contributors were added as Debian Maintainers in the last two months: Congratulations!

23 March 2020

Bits from Debian: New Debian Developers and Maintainers (January and February 2020)

The following contributors got their Debian Developer accounts in the last two months: The following contributors were added as Debian Maintainers in the last two months: Congratulations!