Multiple Subkey Pairs

[Robert J. Hansen]

> I still can read messages friend send me, which are only encrypted to
> e.g. make mass surveillance harder.

Your proposed solution won't work.  Sorry to be so blunt, but that's  
the state of things.

So far there's no credible reporting that any government is doing mass  
surveillance of email content.  Instead, mass surveillance focuses on  
metadata: who's talking to whom, when, with what for a subject line,  
routed through which mail servers, and so on.  GnuPG does not and  
cannot protect against that.

If your concern is mass surveillance -- which is to say, metadata --  
you need to look at other technologies.  GnuPG will not protect your  
metadata.