Granted Patent
Utility
US 4,694,491 · App. 06/710,385
Cryptographic system using interchangeable key blocks and selectable key fragments
Inventors:
Donald R. Horne, John Jeffers
Patented Case
View Patent ↗
Granted: Sep 15, 1987
Filed: Mar 11, 1985
Inventors
Donald R. Horne
John Jeffers
Assignee (at issue)
General Instrument Corporation
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.