encrition /security

I have a customer who needs to have a very secure site, more secure than 
usual, he thinks that having a secure server is not enough so what kind 
of security for his transactions can I offer him? we are not talking 
about money transfers, his bussines is not about money is about 
information, I need to implement for him a very secure way in wich the 
infromatino inserted in to a database  (oracle) be encripted, wheren can 
I get info about this= cheers

Ps my customer in in europe, cheers