A multi-level security system prevents unauthorized use of a computer. A program resident on the computer and implements a user-validation procedure. A key device carries a first serial number and an encryption key. A second serial number is stored in said computer, the second serial number being the...http://www.google.fr/patents/US6216230?utm_source=gb-gplus-shareBrevet US6216230 - Notebook security system (NBS)
