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Ubuntu: automatic password for second encrypted disk

I just encountered the problem that I have to type two passwords at startup, for two encrypted disks. My first disk is encrypted through the Ubuntu installer. After some searching I found the perfect solution for that task. In German its called "Schlüsselableitung", in English derived keys. But perfect solutions often have a big issue why they don’t work, like here. I’m using Ubuntu 16.04 which uses ´systemd´, and that has problems with derived keys. So I found the second most perfect solution for me, using a key-file. Some people argue that this is a security issue, but the derived key is also obtainable with root rights, just like a key-file. And by the way, your private keys of your certificates are also stored on that disks and nearly nobody complains about that.

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Qt Signals & Slots: How they work

The one thing that confuses the most people in the beginning is the Signal & Slot mechanism of Qt. But it’s actually not that difficult to understand. In general Signals & Slots are used to loosely connect classes. Illustrated by the keyword emit, Signals are used to broadcast a message to all connected Slots. If no Slots are connected, the message "is lost in the wild". So a connection between Signals & Slots is like a TCP/IP connection with a few exceptions, but this metaphor will help you to get the principle. A Signal is an outgoing port and a Slot is an input only port and a Signal can be connected to multiple Slots.

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How to start with Qt?

In this series I’ll give you a starting point on working with with Qt. Like I mentioned in Why I love the Qt framework I had a hard time at the beginning. I want to give you an easier start with this awesome peace of technology. This page will serve as an index for the whole series of tutorials and explanations. As more posts follow this page will be updated. I know there are plenty of tutorials on Qt, but maybe I’ll explain some things in a way you understand better. Continue reading