preparse process - parsing with credidentials

I'm working on preparsing in vlc using an external dedicated "preparse process".
When vlc has to parse an item, and the access require credidentials, as a file over smb.
It only works if the user already allowed and store the credidentials associated to the file, in the system keystore solution.
Since it's an other processus, it seems the temporary access vlc gain when a user enter credidentials, is only valid in the vlc processus/context.

So I need a solution to share this temporary access across vlc and the preparse process.
Since thoses two processus are communicating through pipes().
I'm not sure it can be secured well enough, to share creditentials this way, on all platforms that will use the preparse process (windows, linux, osx).

Which solutions can be considered, to share the "temporary" access the vlc keystore dispose, between processus, securely ?