将数据从MySQL数据库安全传输到iOS设备

I am trying to build an iOS application that will pass data back and forth from the web server (or the database directly). There is very sensitive information being passed (like money information and passwords). In the past I have used JSON to connect to a database before using php files that use GET functions. I thought about using POST - but both seem pretty unsafe. Is there a better way? I have never worked with such sensitive information.I am trying to build an iOS application that wi