Hi there,
I read this blog post
http://monty-says.blogspot.com/2014/05/for-your-eyes-only-or-adding-better.html
and wanted to inform you that we at Google has developed on-disk/block-level encryption for Innodb, aria (as used by temporary tables), binlogs and temp-files.
The code is not yet published, but we expect it to be within a few weeks or so.
We (of course?) think that it would be better if you instead of developing new code
spent the time testing/reviewing ours.
I'm happy to answer questions on the topic,
and will let you know once we've published it.
/Jonas
ps.
Ian talked about this at percona,