I need a way to store data from an userscript, so that the site it is working on cannot access that data. I'm creating a script that would encrypt facebook's chat and i need to keep encryption keys between sessions. cookies and local storage can be accessed by facebook's scripts. GM_setValue does not work on opera.
Found answer here:
Access root domain's localStorage from subdomain
http://www.opera.com/docs/userjs/specs/#scriptstorage
I will just use GM_setValue for FF and scriptStorage for Opera