The flash.system package contains classes for accessing system-level functionality, such as security, garbage collection, etc.

 fscommand Lets the SWF file communicate with either Flash Player or the program hosting Flash Player, such as a web browser.
 ApplicationDomain The ApplicationDomain class is a container for discrete groups of class definitions.
 Capabilities The Capabilities class provides properties that describe the system and runtime that are hosting the application.
 ImageDecodingPolicy The ImageDecodingPolicy class provides values for imageDecodingPolicy in the LoaderContext class.
 IME The IME class lets you directly manipulate the operating system's input method editor (IME) in the Flash runtime application that is running on a client computer.
 IMEConversionMode This class contains constants for use with the IME.conversionMode property.
 JPEGLoaderContext The JPEGLoaderContext class includes a property for enabling a deblocking filter when loading a JPEG image.
 LoaderContext The LoaderContext class provides options for loading SWF files and other media by using the Loader class.
 MessageChannel The MessageChannel class provides a mechanism for a worker to communicate with another worker.
 MessageChannelState This class defines constants that represent the possible values for the MessageChannel class's state property.
 Security The Security class lets you specify how content in different domains can communicate with each other.
 SecurityDomain The SecurityDomain class represents the current security "sandbox," also known as a security domain.
 SecurityPanel The SecurityPanel class provides values for specifying which Security Settings panel you want to display.
 System The System class contains properties related to local settings and operations.
 SystemUpdater The SystemUpdater class allows you to update modules of the Flash Player, such as the DRM module for Adobe Access, as well as the Flash Player itself.
 SystemUpdaterType The SystemUpdaterType class provides constants for a system update.
 TouchscreenType The TouchscreenType class is an enumeration class that provides values for the different types of touch screens.
 Worker A Worker object represents a worker, which is a virtual instance of the Flash runtime.
 WorkerDomain The WorkerDomain class provides a way to create Worker objects and access them.
 WorkerState This class defines constants that represent the possible values of the Worker class's state property.