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The Economist provides a nice Android application, however: the cache contents (saved on the sd-card by the application) are 'encrypted' for some silly reason. We will fix that within a few minutes.

Analyzing the data

The 'encrypted' data is stored at /your/phone/com.economist/library/$date, let us have a look at some cached files: hmm.. doesn't look like a GIF, let's try some other file... Drat: also just some binary data, but wait: the first few bytes of both images are exactly the same! So let's have a look at some XML file: How nice: The first few bytes are also exactly the same for both files... but they wouldn't be stupid enough to use XOR to 'protect' such files, or would they?
Guessing the first few bytes of an XML-File is very easy and therefore we can calculate the 'key': Wow: Single-Byte XOR - WTF did they even try to 'encrypt' them?

'Decrypting' the data

'Decrypting' the data is rather easy: Save this script als 'deconomist.pl'... ..and run:
..some examples:




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