Abstract: The present invention relates to a method and system for protecting and limiting the execution of a software program only to an authorized user. The software program can be provided in any suitable software form, such as a binary code, or it can be written in a high level program language. In the present invention, the binary code of the program is analyzed and partitioned into parts, some of which are selected to be protected. The protected parts are selected so that during any execution of the software, at least some of the selected parts must be present and executed. The protected code is encrypted and at least partially saved on an attached secured computing device such as a secured disk on key with a small processor or controller, or a smart flash drive.