From 83ff6fea00de5ab0b82704c4e8aa4258c9e504d6 Mon Sep 17 00:00:00 2001
From: Moshe Kaplan <mk.moshe.kaplan@gmail.com>
Date: Wed, 16 Nov 2016 09:04:17 -0500
Subject: [PATCH] Additional error output for failed encryption

---
 PyPDF2/pdf.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/PyPDF2/pdf.py b/PyPDF2/pdf.py
index d1751a7..58f4ca6 100644
--- a/PyPDF2/pdf.py
+++ b/PyPDF2/pdf.py
@@ -2057,7 +2057,7 @@ class PdfFileReader(object):
         if encrypt['/Filter'] != '/Standard':
             raise NotImplementedError("only Standard PDF encryption handler is available")
         if not (encrypt['/V'] in (1, 2)):
-            raise NotImplementedError("only algorithm code 1 and 2 are supported")
+            raise NotImplementedError("only algorithm code 1 and 2 are supported. This PDF uses code %s" % encrypt['/V'])
         user_password, key = self._authenticateUserPassword(password)
         if user_password:
             self._decryption_key = key