在客户端托管时的数据库安全性

I have a database along with REST API for clients to access the data. For performance and other reasons, I need to move the application along with the data to the client's physical server. Is there a way for me to encrypt the data in the database, so the only way the client can get access to it is through API that I expose, and not by cracking MySql and getting at raw data. I do not want the client to see the data stored on my DB, as I feel they will steal it or share it. What can I do to accomplish that? I have a database along with REST API for clien