Patents by Inventor Thomas C. Donald

Thomas C. Donald has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Software protection system
    Patent number: 4471163
    Abstract: A protection system for controlling the operation of a digital computer as to a particular program wherein a program "lock" interfaces with the computer and authorizes the operation in response only to a selected relation between a number in the program, a number in the lock, and a third number, a "key", supplied to the lock and which bears a selected relation to both the program number and lock number.
    Type: Grant
    Filed: October 5, 1981
    Date of Patent: September 11, 1984
    Inventors: Thomas C. Donald, Henry W. Donald