Category: Hacking

Learning C // Part 2

Within the last days I read many questions about C on Stackoverflow. Most of them are typical beginners issues struggling with arrays and pointers. Some time ago I wrote this article about »Learning C« which suggests some basic statements. Based on these Stackoverflow issues I wrote some additional statements which should improve your way of …

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Cairo Graphics and X11/Xlib

This article explains how to open an X11 window using Xlib and shows how to create graphics output with Cairo graphics. Cairo Graphics — also simply called libcairo — is a very powerful 2D graphics library. Among many graphics primitives (such as lines, curves,…) the approach of libcairo is to separate the graphic functions from …

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AVR Linker: out of range error

This article describes two common reasons for the out-of-range AVR linker error message and provides solutions. Although this article is specific to the AVR core, the same problems occur on most processor types. I’m currently preparing a course, teaching students about assembly language. I chose to use Arduino as development platform which is equipped with …

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Native Assembler Programming on Arduino

This article is about programming an Arduino board natively in pure Assembler without carrying the rucksack of standard libraries and functions. Using a simple example and an Arduino Uno board, I will show how to assemble, link, and upload your code to the board without using the Arduino development environment. This article does not teach …

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Cloudbetreiber sind verantwortlich!

Große Aufregung herrscht gerade, wegen Naktfotos von einigen Hollywood-Stars, in erster Linie deshalb, weil diese von einem bösen Hacker aus der Apple-Cloud abgesaugt wurden. Natürlich ist es nicht erlaubt, fremde Daten ohne Erlaubnis aus einer Cloud zu kopieren, ein Bankraub ist ja auch nicht erlaubt. Das ist grundsätzlich auch richtig so, allerdings hinkt dieser Vergleich …

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Nextgen Gallery Images Don’t Show Up In Lightbox

The Nextgen Gallery1 is an excellent plugin for WordPress. It allows to organize series of images to galleries and these can be inserted into posts as a whole are just into the text as single pictures.2 The Nextgen gallery is updated regularly. I’m using it on several blogs and it seems to be pretty stable. …

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Was wir aus Heartbleed lernen sollten

Heartbleed ist der Codename für einen fatalen Softwarebug in OpenSSL, eine Funktionsbibliothek für kryptografische Algorithmen. Kryptografie ist ein Überbegriff für Verfahren zur Verschlüsselung und Authentifikation die in Wahrheit aus einer Vielzahl komplexer mathematischer Algorithmen zusammengesetzt werden. OpenSSL stellt diese Algorithmen als Bausteine zur Verfügung, die man für eine sichere Datenübertragung benötigt. Heartbleed heißt diese Sicherheitslücke …

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p = &(*p)->next; // Learning C

Looking back on 25 years of experience in C programming I consider C still to be the queen of languages to write complex, fast, and powerful programs although there are many other powerful new languages today. C++ is even more powerful in several applications but it bears the risk for novice users who are familiar …

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Accounts Disappear After Reboot

Have you ever had or do you currently have the problem that some of your accounts disappeared after a reboot of your Android phone? If yes then probably here is the solution. A few days ago I “played” a little bit with my Android phone. The next day I recognized that several of my accounts …

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Applied Social Engineering

On our university, I am running a Plog — this is the paper version of a Blog 😉 (see image on the right side). I put various articles there, mainly those which I post here but also other interesting stuff which I find on the internet. While waiting for the next course, students may read …

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