RE: [pdf-devel] Encryption filters

[Leonard Rosenthol]

You will need to have code that decodes the data in a encrypted stream -
however, the seed values (etc.) for a stream encrypted by a stream
filter come from local dictionary values while they come from a "global"
location in a standard encryption.

Leonard

-----Original Message-----
From: address@hidden [mailto:address@hidden 
Sent: Monday, July 28, 2008 11:34 PM
To: Leonard Rosenthol
Cc: David Vazquez; address@hidden
Subject: Re: [pdf-devel] Encryption filters


Hi Leonard.

   Just remember that normal PDF encryption does NOT use "Crypt
   Filters", but instead simply encrypts all strings and streams.
   "Crypt Filters" are only ever used as Identity, in the case of
   unencrypted metadata, or on embedded files (for a secure envelope).

Thanks for the note.

As I understand it we need to implement the crypt filters anyway,
since the standard allow to encrypt individual streams and embedded
files are contained in streams.