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). Not that other options aren't supported - but those are the only cases where Acrobat will create them.
Leonard -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of David Vazquez Sent: Monday, July 28, 2008 5:22 AM To: [EMAIL PROTECTED] Cc: pdf-devel@gnu.org Subject: Re: [pdf-devel] Encryption filters [EMAIL PROTECTED] writes: > Could you please write down a summary of all the needed parameters > for both filters? Of course :) In the encryptation dictionary, both filters involves the use of following parameters: - The entry V specifies the type of algorithm to be used. It should be 4 in order to security handler will define the behaviour. - CF is a dictionary whose keys and values are crypt filter names and crypt filter dictionaries respectively. - StmF is the name of the crypt filter to encrypt streams by default. (the crypt filter should be a CF key entry) - StrF, idem for string. A crypt filter dictionary contains (amongst others) a key named CFM, whose value could be one of three: - None - V2 (for RC4/ARC4) - AESV2 (for AES) Finally in filter dictionarity we found a key `name' which let us declare what crypt filter we want use. It is the name of a crypt filter defined in CF. I think it's all! :)
