1
John D Wiedemer: High security pay television system. Signal Security Technologies, Isaksen Lathrop Esch Hart & Clark, September 22, 1987: US04696034 (207 worldwide citation)

A high security pay television system is provided in which subscribers are provided with a decoder and with periodically changed removable memory modules. The decoder only functions to properly descramble the scrambled broadcast signal when a changeable system-wide code is available in the decoder. ...


2
John D Wiedemer: Billing system for computing software. Signal Security Technologies, Quarles & Brady, October 13, 1992: US05155680 (198 worldwide citation)

A computer software security and billing system is disclosed in which the application program is enciphered in accordance with an algorithm driven by a numeric key. The user's computer is provided with a hardware security module and a removable billing module, both of which carry unique codes. A sec ...