Described are techniques and mechanisms for enforcing trust between an application and a library loaded by the application. Very generally stated, the application declares one or more trusted code groups (“TCGs”) of which a library must be a member to be authorized for execution with the application. Libraries that are authorized to assert membership in one or more TCGs include a secure indicator of that membership. As the application executes and attempts to load a library, that libraries membership in a TCG authorized by the application is verified prior to loading the library.