An apparatus and method of disabling an unauthorized copy of a computer program. A set of numbers having an uncommon mathematical property is defined. For authorized copies, one of these numbers is written to a pre-determined location in the computer program. Whenever a copy of the computer program is...http://www.google.co.uk/patents/US5287408?utm_source=gb-gplus-sharePatent US5287408 - Apparatus and method for serializing and validating copies of computer software
