Archive for the 'Computer' Category


Wednesday, August 31st, 2016

A little while ago WhatsApp introduced end-to-end encryption for messaging, which was very welcome to people like me who are concerned about their privacy. A few days ago, though, they changed their terms of service and are now going to use data for ad targeting on Facebook. Ugh. Read more about it on

TechCrunch: WhatsApp to share user data with Facebook for ad targeting — here’s how to opt out.

However, you cannot opt out of all data sharing, just some. Time to look for an alternative!

I’ve already been using Threema (which costs 2,99€ for iPhone), but now a friend pointed me to Telegram, which is not only free and available for virtually all platforms (including desktop computers), it also is open source, uses encryption and is cloud-based, so you can access your messages from multiple devices.

I installed it immediately and plan to delete WhatsApp before having to agree to their new terms of service after telling as many as my contacts as possible about Telegram.

A second moon

Tuesday, June 21st, 2016

Jet Propulsion Lab/NASA: Small Asteroid Is Earth’s Constant Companion.

“A small asteroid has been discovered in an orbit around the sun that keeps it as a constant companion of Earth, and it will remain so for centuries to come.

As it orbits the sun, this new asteroid, designated 2016 HO3, appears to circle around Earth as well. It is too distant to be considered a true satellite of our planet, but it is the best and most stable example to date of a near-Earth companion, or “quasi-satellite.””

The picture of the orbit reminded me of my first (and second-to-last) programming project: During my first year of university I had to write a program that calculated orbits of a satellite influenced by the gravity of sun and earth, also known as three-body-problem. Even though I checked my work again and again, the stupid program wouldn’t turn out the right (periodic or chaotic) orbits, so I had to get an extension on the deadline for handing in the project. Took me two whole days to find the sign error.

And now you know why I hate programming. 😉


Monday, March 7th, 2016

The first ransomware for Mac OS X has been found.

MetaFilter: OS X Ransomware. “First OS X ransomware detected in the wild, will maliciously encrypt hard drives on infected Macs.”

9to5Mac: First OS X ransomware detected in the wild, will maliciously encrypt hard drives on infected Macs [Update: How to fix].

“OS X users have today been hit with the first known case of Mac ‘ransomware’ malware, found in the Transmission BitTorrent client released last week. Infected versions of the app include ‘KeyRanger’ malware that will maliciously encrypt the user’s hard drive after three days of being installed. The malware then asks for payment to allow the user to decrypt the disk and access their data — the ‘ransom’.”

Ransomware has been around for several years in one form or another, but seems to have become much more popular in the past few months. One of my favorite podcasts reported on this problem back in the fall:

Radiolab on September 21, 2016: Darkode.

“It would seem that hackers today can do just about anything they want – from turning on the cellphone in your pocket to holding your life’s work hostage. Cyber criminals today have more sophisticated tools, have learned to work collaboratively around the world and have found innovative ways to remain deep undercover in the internet’s shadows. This episode, we shine a light into those shadows to see the world from the perspectives of both cybercrime victims and perpetrators.”

You can listen to, stream or download the episode for free.

Deutsche Welle on February 25, 2016: Hackers hold German hospital data hostage.

“Several hospitals in Germany have come under attack by ransomware, a type of virus that locks files and demands cash to free data it maliciously encrypted. It will take weeks until all systems are up and running again.”

Die Zeit: Wir haben Eure Daten! “Eine neue Form der Erpressung hat sich etabliert. Cyberkriminelle legen Computer lahm und verlangen Lösegeld. Was passiert, wenn es ein Krankenhaus trifft – eine Rekonstruktion.” Von Karen Grass.

Ads that use inaudible sound

Tuesday, November 17th, 2015

If this is true, I’m going to knit myself a tinfoil hat. And one for my laptop, and one for my tablet, and one for my cellphone.

Ars Technica: Beware of ads that use inaudible sound to link your phone, TV, tablet, and PC. “Privacy advocates warn feds about surreptitious cross-device tracking.” By Dan Goodin.

“The ultrasonic pitches are embedded into TV commercials or are played when a user encounters an ad displayed in a computer browser. While the sound can’t be heard by the human ear, nearby tablets and smartphones can detect it. When they do, browser cookies can now pair a single user to multiple devices and keep track of what TV commercials the person sees, how long the person watches the ads, and whether the person acts on the ads by doing a Web search or buying a product. Dan Goodin reports for Ars Technica on cross-device tracking software already in use today.”

Link via and discussion over at MetaFilter.

Babylonisches Wurzelziehen im 21. Jahrhundert

Thursday, November 5th, 2015

Das nach dem griechischen Mathematiker Heron von Alexandria benannte Heron-Verfahren zur näherungsweisen Berechnung von Quadratwurzeln war bereits ca. 1750 v. Chr. den Babyloniern bekannt und wurde um 100 n. Chr. von Heron in seinem Werk Metrica beschrieben.

Heute gehört es zumindest in Rheinland-Pfalz noch zum Lehrplan des Gymnasiums (Jahrgangsstufe 9, irrationale Zahlen), wird allerdings gerne mit modernen Hilfsmitteln kombiniert. Dr. Jürgen Roth, Professor für Didaktik der Mathematik an der Universität Koblenz-Landau, hat zu diesem Zweck ein Geogebra-Arbeitsblatt entwickelt, das online verfügbar ist und direkt von Schülern verwendet werden kann: Heron-Verfahren zur Quadratwurzelberechnung.

Geogebra gibt es übrigens für Windows, MacOS und Linux sowie für Tablets unter iOS, Windows und Android. Für Smartphones gibt es z. T. Beta-Versionen.