PDF AES stream

Hello,
I have a problem with using of a class PDFAESStream. I have an encrypted book and I'm trying to open it. For this purpose I use this code:

The bookPath variable is an existing path to the book, which is encrypted via AES.
The open() method always returns false. For encryption, I simply used AES/CBC/PKCS5Padding. The open() method still returns false, because the condition

is always true.

Where is the problem?
Thank you in advance for your reply.

PDFAESStream is customer format file.
you shall use PDFAESStream.ImportFromFile() to create a encrypted PDF file.

to create encrypted PDF file codes like:
PDFAESStream stream = new PDFAESStream();
stream.ImportFromFile( "path-name" );
stream.ExportToFile( "an other path-name" );
stream.close();

to open encrypted PDF file codes like:
PDFAESStream stream = new PDFAESStream();
stream.open( "path_name", password );
Document doc = new Document();
doc.OpenStream( stream, ... );
doc.Close();
stream.close();

PDFAESStream may used in pure java envirment on linux/windows and so on.

Ok, thank you for your reply.

I tried your code, but it does not work. A method ImportFromFile returns false. The problem is with this line:

m_file is null. I use exactly this code:

The variable inputPath is path of the book and this path exists.

sorry, forgot something.
codes:

This code works. It creates a new file with length 4096 bytes. Is this correct? I thought that it will create a new file - the encrypted PDF document with AES.

there are example in ReaderActivity.java
some codes are commented.
//byte key[] = new byte[16];
//stream.open("/sdcard/ttt.pdf", key);
//stream.ImportFromFile("/sdcard/test.pdf"); //encrypt to /sdcard/ttt.pdf
//stream.ExportToFile("/sdcard/test1.pdf"); //decrypt to /sdcard/test1.pdf

these codes shall tested.