Rhein-Main.Net – Ein Tag. Ein Dienst.

Rhein-Main.Net – Ein Tag. Ein Dienst.


Johannes Bauer

Johannes Bauer

Working at Bosch Software Innovations GmbH in Immenstaad am Bodensee, Germany

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luksipc is a tool to convert (unencrypted) block devices to (encrypted) LUKS devices in-place (therefore it’s name LUKS in-place conversion). This means the conversion is performed without the need of copying all data somewhere, recreating the whole disk (i.e. create a LUKS device, create a new filesystem on the mapped LUKS device, copy all data back). Instead, the process is reduced to:

Unmounting the filesystem
Resizing the filesystem to shrink about 2 megabytes (1028 kB for current LUKS versions to be precise)
Performing luksipc
Adding custom keys to the LUKS keyring

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xpdf protection

If you are the proud owner of a proprietary PDF-Creator like “Adobe Acrobat” you probably have noticed that it gives you the option to make the resulting PDF protected in a way that you cannot copy any text from it or that you cannot extract the pictures within. What a nice little feature.

Now what this technically does is to set a flag in the PDF telling the reader program “Please don’t let the mean user copy any content from me!”. However, the whole process relies on the reader progam (like “Adobe Acrobat Reader” or “xpdf”, in our case) to obey the request of the PDF creator.

Now at this point, I got really annoyed by xpdf. Because it really does obey the completely non-sensical request of the PDF creator. Probably because of some legal trouble which Adobe might give them if they did not obey it. But logically there is absolutely no reason to restrict the extraction of text of graphical images from a PDF file. Text I could read and type it in again. Pictures I could photograph off my PC screen. It’s completely moronic. It’s Adobe.

Plus some people at my college think it’s protecting their documents well. They seem to believe that content which is made for education should under no circumstances leak to the outside – somebody could maybe learn something! It would be a disaster! That this is a stupid idea is obvious. This patch just proves my point.