A technique to prevent illicit copying of a copy-protected CD-ROM into a
computer-readable storage drive is presented. In accordance with the
present invention, when an authentic copy-protected CD-ROM is inserted
into a CD drive and the content of the copy-protected CD-ROM is installed
onto a hard disk drive that is linked to the CD drive, the Central
Processor Unit (CPU) executes the installer instructions residing in the
CD-ROM to create a license file in the hard disk drive. For security
reasons, the content of the CD-ROM (e.g., the executable file of the
application) is encrypted. When the content of the CD-ROM is copied into
the hard disk drive, it remains encrypted. The license file essentially
acts as a timer to monitor a predetermined time interval that has been
programmed into the license file. If a user attempts to launch the
encrypted copied application residing in the hard drive at any time prior
to the expiration of the predetermined time interval, the license file
readily supplies the key code to enable a filter to decode the encrypted
installed application thereby allowing the application to launch. At the
expiration of the predetermined time interval, the license file withholds
the key code therefore not allowing the installed application to be
decrypted and successfully launched. The predetermined time interval can
be reset by reinserting the copy-protected CD-ROM into the CD drive to
reset the time interval.