Merge pull request py-pdf#210 from underdogio/dev/copy.encryption.sqwished

Added decryption key copying for PdfFileMerger

Author: mstamy2

PyPDF2/merger.py

@@ -109,6 +109,7 @@ def merge(self, position, fileobj, bookmark=None, pages=None, import_bookmarks=T
         # it is a PdfFileReader, copy that reader's stream into a
         # BytesIO (or StreamIO) stream.
         # If fileobj is none of the above types, it is not modified
+        decryption_key = None
         if isString(fileobj):
             fileobj = file(fileobj, 'rb')
             my_file = True
@@ -123,11 +124,15 @@ def merge(self, position, fileobj, bookmark=None, pages=None, import_bookmarks=T
             filecontent = StreamIO(fileobj.stream.read())
             fileobj.stream.seek(orig_tell) # reset the stream to its original location
             fileobj = filecontent
+            if hasattr(fileobj, '_decryption_key'):
+                decryption_key = fileobj._decryption_key
             my_file = True
 
         # Create a new PdfFileReader instance using the stream
         # (either file or BytesIO or StringIO) created above
         pdfr = PdfFileReader(fileobj, strict=self.strict)
+        if decryption_key is not None:
+            pdfr._decryption_key = decryption_key
 
         # Find the range of pages to merge.
         if pages == None: