I don’t normally quote The Register, but I was clearing tabs and found this article: 350 DBAs stare blankly when reminded super-users can pinch data. It is an interesting read, telling you that there are many Snowden’s in waiting, possibly even in your organisation.
From a MariaDB standpoint, you probably already read that column level encryption as well as block level encryption for some storage engines are likely to come to MariaBD 10.1 via a solution by Eperi. However with some recent breaking news, Google is also likely to do this – see this thread about MariaDB encryption on maria-discuss.
Google has already developed on-disk/block-level encryption for InnoDB, Aria (for temporary tables), binary logs and temporary files. The code isn’t published yet, but will likely happen soon, so clear benefits of open source development principles.