Encrypted PDF with milibrisreader

[Pozz]

Milibris: http://www.milibris.com/en/

Hi everyone,

I have an account on a french press publisher, and I am able to download the issues in digital format. With a rooted Android device, I have copied the files to my computer to have a closer look. Here's the content of the folder:
-"key.blob" file (Obviously the key used to decrypt the pdf files)
-One PDF file for each page of the issue.

But when I try to open a PDF file, I got an error.
Do you have any idea on how to open these files with any programs ?
If you wan't more informations about the app, the libraries used etc. don't hesitate, thanks!