Security :: Data Encryption From Transaction To Backup Level?

Our client is having requirements that data should be encrypted through-out the process (from transaction level to backup level).

Requirements are as below -

1) Data should be encrypted and can be access only through application (through front end).
2) Even if pl/sql, sql installed, developer user cannot able to fetch data from database.
3) Even DBA, should not have access to fetch the data from the database.
4) Only assigned DBA, should fetch details from database (provided he/she should have details of database as well as application's user / password).
5) It should be restricted by ip and user details (such as ip of application server with user/password of user).
6) Changes should be purely done from database level only.