Thread: KindleUnpack (MobiUnpack): Extracts text, images and metadata from Kindle/Mobi files
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Old 03-14-2012, 03:06 AM   #322
kovidgoyal
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The first 1040 bytes of the *compressed* font are XORed with a (seemingly randomnly generated) key. I have committed code to calibre to de-obfuscate them. Given that the MOBI format itself is a much harder form of obfuscation, I have no idea why amazon felt the need to implement a XOR on top of it, but then I have no idea why Amazon makes have the technical decisions it does...
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