I'm not a security guru, but the most common scenario (even today, that big data and NoSQL/Graph dbs thrive) is a website running on a SQL (with some additional memcached/Redis or Mongo?).<p>Say I encrypt the entries... Since the database runs in local host, if the host is compromised and subsequently 'rooted', what exactly does database encryption offer?<p>The intruder will sniff/find the encryption key(s) since the key must be somewhere inside the application or in memory (don't know how, but I'm sure it's possible) in order to be able to decrypt data on the fly. The way I see it it's just added complexity for the admin with no gain.<p>Is there any way of defending an SQL database even when the host is compromised?