The present invention secures applications from executing illegal or harmful operation requests received from a distrusted environment, thereby, preventing an application from damaging itself, other applications, performance, files, buffers, databases, and confidentiality of information. An operation reverse engineering layer is positioned in front of an application in a trusted environment and between the application and the incoming application operation requests that are received from an unknown or distrusted environment. The operation reverse engineering layer checks the requests for either form, content, or both, to insure that only legal and harmless requests will pass to the given application. Hardware, software, or both, are employed to implement the operation reverse engineering layer.