pyPdf fails to read non-encrypted document raising "file has not been decrypted"

[logari81]

Trying to get a reference of the first page of the attached pdf document raises the exception "file has not been decrypted" even though the document is not encrypted. See below:

>>> input = pyPdf.PdfFileReader(file("DS-0157.pdf",'rb'))
>>> page = input.getPage(0)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/var/lib/python-support/python2.6/pyPdf/pdf.py", line 353, in getPage
    self._flatten()
  File "/var/lib/python-support/python2.6/pyPdf/pdf.py", line 499, in _flatten
    catalog = self.trailer["/Root"].getObject()
  File "/var/lib/python-support/python2.6/pyPdf/generic.py", line 466, in __getitem__
    return dict.__getitem__(self, key).getObject()
  File "/var/lib/python-support/python2.6/pyPdf/generic.py", line 165, in getObject
    return self.pdf.getObject(self).getObject()
  File "/var/lib/python-support/python2.6/pyPdf/pdf.py", line 555, in getObject
    raise Exception, "file has not been decrypted"
Exception: file has not been decrypted

[logari81 (logari81)]

I 've found out that the document is recognized from pyPdf as encrypted. I tried to decrypt it using an empty string as password and it worked. Trying to decrypt the document with any other string failed.

>>> input.getIsEncrypted()
True
>>> input.decrypt('')
1
>>> input.decrypt('dcdsfvcfd')
0

[thebitguru (farhan)]

I believe this is by design. i.e. you have to decrypt using empty string and if that is the same as the user password in the PDF file then you are good, otherwise, you have to request the password from the user (either user or owner).