A method of authorizing access in system and application services of an Android system, the method comprising: receiving a request for access to an Application Programming Interface, API, of a service from a caller; and obtaining the Process Identity, PID, User Identity, UID, package, and SEInfo of the caller; obtaining authorization information from a file; checking whether the SEInfo is authorized for the service; if the SEInfo is authorized for the service, returning a type of the caller; if the SEInfo is not authorized for the service, checking whether the package is authorized for the service; if the package is authorized for the service, checking whether the SEInfo matches in the file; if the SEInfo matches in the file, returning the type of the caller; if the SEInfo does not match in the file, denying the API of the service; if the package is not authorized for the service, checking the SEInfo is authorized for a method; if the SEInfo is authorized for the method, returning a type of the caller; if the SEInfo is not authorized for the method, checking whether the package is authorized for the method; if the package is authorized for the method, checking whether the SEInfo matches in the file; if the SEInfo matches in the file, returning the type of the caller; if the SEInfo does not match in the file, denying the API of the service; if the package is not authorized for the method, deny the API of the service. receiving a request for access to an Application Programming Interface, API, of a service from a caller; and obtaining the Process Identity, PID, User Identity, UID, package, and SEInfo of the caller; obtaining authorization information from a file; checking whether the SEInfo is authorized for the service; if the SEInfo is authorized for the service, returning a type of the caller; if the SEInfo is not authorized for the service, checking whether the package is authorized for the service; if the package is authorized for the service, checking whether the SEInfo matches in the file; if the SEInfo matches in the file, returning the type of the caller; if the SEInfo does not match in the file, denying the API of the service; if the package is not authorized for the service, checking the SEInfo is authorized for a method; if the SEInfo is authorized for the method, returning a type of the caller; if the SEInfo is not authorized for the method, checking whether the package is authorized for the method; if the package is authorized for the method, checking whether the SEInfo matches in the file; if the SEInfo matches in the file, returning the type of the caller; if the SEInfo does not match in the file, denying the API of the service; if the package is not authorized for the method, deny the API of the service. if the package is authorized for the service, checking whether the SEInfo matches in the file; if the SEInfo matches in the file, returning the type of the caller; if the SEInfo does not match in the file, denying the API of the service; if the package is not authorized for the service, checking the SEInfo is authorized for a method; if the SEInfo is authorized for the method, returning a type of the caller; if the SEInfo is not authorized for the method, checking whether the package is authorized for the method; if the package is authorized for the method, checking whether the SEInfo matches in the file; if the SEInfo matches in the file, returning the type of the caller; if the SEInfo does not match in the file, denying the API of the service; if the package is not authorized for the method, deny the API of the service. <EOS>