At loss about CS specialization/sub-field
Honestly, you sound like someone who is looking for a Magic Bullet to Save The World, not someone who is really informed about or interested in computer science.  You sound like someone in love with the idea of computer science research, but with no real idea what computer science research is.  Computer security against aliens?  Quantum computing?  Artificial intelligence?  These are all dangerously close to science fiction.  There's tons of good research in all those areas, but nothing — in any of those areas — is close to "saving the world", and everything interesting — in all of those areas — requires a fair bit of mathematical maturity.  Sorry, but if you don't like math, you won't like real AI research, or real security research, or real quantum computing research.

If you want to do research, and really do it well, you have to love your tools.  You have to love the math; you have to love the code; you have to love the nights in the lab; you have to love the balky experimental equipment.  You have to love feeling stupid, because researchers spend 99% of their time feeling stupid; they're at the bleeding edge of what mankind understands about Reality, so of course they don't really know what they're doing.  You have to love to work in the face of almost certain failure.  You have to take the world's ignorance, especially your own personal ignorance, as motivation, not frustration.  You have to get over the idea that you are going to Save to World, because you aren't, but you do the work anyway, because you can't not do the work; it's in your blood; it's who you are.

If that's not you, don't bother.  There are much better ways to make money.  There are much better ways to help people.  There are much better ways to be happy than to do something you don't really love because you think it's Cool and Important.

But if you really can't live without doing it, then you really have no choice—do it, and do it well.  And who knows; you may save the world after all!  (But probably not.)