Billings has made a pioneering contribution to the field of computer security with his Hierarchical Security Protocol (HSP), a method of protecting sensitive computer data utilizing a hardware-based, key management system. The system allows multiple users the means to decrypt shared data without distribution of the encryption keys and to do so in a hierarchical system that can be managed in hardware devices.
The HSP technology resulted in the formation of GoldKey Security Corporation, which develops and manufactures security tokens now used by the US Government, industry, and others to protect sensitive data.