[gs-cvs] rev 7112 - trunk/gs/lib

[dan at ghostscript.com]

Author: dan
Date: 2006-10-18 00:01:10 -0700 (Wed, 18 Oct 2006)
New Revision: 7112

Modified:
   trunk/gs/lib/pdf_sec.ps
Log:
Fix for 688880 Encrypted PDF can not be processed.

DETAILS:

The problem file specifies both V = 1 and and a Length = 128
bits in the encryption dict.  This is contradictory since page 93 of
the PDF 1.6 spec says that if V = 1 then the key length should be
40 bits.

This change ignores the the Length value if V = 1.  This matches the
observed behavior with Adobe Acrobat 7.0.


Modified: trunk/gs/lib/pdf_sec.ps
===================================================================
--- trunk/gs/lib/pdf_sec.ps	2006-10-17 13:33:02 UTC (rev 7111)
+++ trunk/gs/lib/pdf_sec.ps	2006-10-18 07:01:10 UTC (rev 7112)
@@ -84,7 +84,11 @@
 
 % Get length of encryption key in bytes
 /pdf_key_length {    % pdf_key_length <key_length>
-  Trailer /Encrypt oget /Length knownoget { -3 bitshift } { 5 } ifelse
+  Trailer /Encrypt oget
+  dup /V knownoget not { 0 } if 1 eq
+  { pop 5 }	% If V == 1 then always use 40 bits
+  { /Length knownoget { -3 bitshift } { 5 } ifelse }
+  ifelse
 } bind def
 
 % Algorithm 3.2