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.
