First, I have programmed front ends for MySQL for over a decade and while I like that system, you lead with security which I'm wondering about a lot today. That is, as I read http://forums.cnet.com/7723-6132_102-588972/news-march-20-2013/?tag=contentBody;threadListing and my contribution there I don't think this is the app's responsibility to secure your PC.
You see this issue with JAVA as the pundits weigh in that the language or run-time should secure what is a very insecure PERSONAL computer.
That out of the way, Why SQL at all? Are you going to learn SQL?
I'd like to organize some data I have into an easy to search database, but I'd also like it to be very secure from anyone both local and remote. OpenOffice and LibreOffice Base looks like nice free software but doesn't seem secure enough, and Microsoft Access doesn't appear too much better. So far from my research Microsoft SQL Server might be the best bet, but I'd like to hear another's opinion on what options are available.
I'm completely new to the world of database technology. If there is both a safe and affordable option I would be very happy to hear of it. Thank you!