An app is secured on a mobile device by being deconstructed or unbundled into multiple modules, where a module is a segment of app code that performs a particular function. It is then determined which modules from the multiple modules perform some type of security function, for example, a function dealing with confidential or security-related data. These modules, forming a group of modules, are loaded into a trusted execution environment. The app is then re-bundled so that it has the first plurality of modules and the second plurality of modules. The app executes in a manner where the high security functions execute so that break points cannot be inserted into the app code. The re-bundling is done automatically in an app security wrapping process. Security constraints are added to the app.