Re: [pdf-devel] Encryption filters

[David Vazquez]

address@hidden writes:

>    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)
>
> So in the end we would need to write stm filters for RC4/ARC4 and AES,
> isnt it? 
>

I think we need both stm filters and string encryptation functions.


>    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 dont fully understand. What is the difference between a "crypt
> filter dictionary" and a "filter dictionary"?
>

I think that filter dictionary is bound to a stream. It specifies the
name of the crypt filter we will use in the respective stream.

Each crypt filter is defined in as an entry in a global
dictionary. The key is the name and the value is the _crypt filter
dictionary_. This dictionary let us set parameters as the algorithm to
use (eg: AES, AR4).


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