Hierarchical key assignment without public-key cryptography

VLSI chips make possible the hardware devices employed in today's computing environment for security functions. Controlling access in a hierarchy is an interesting research topic in computer security. Many investigations have been published in the literature with solutions involving assigning cryptographic keys to users at different access clearance levels. However, the existing schemes require a large number of costly arithmetic operations with large integers. This type of system is difficult to implement in a chip with lower computation ability. In this paper, we present a solution, suitable for a low cost chip, to the hierarchical control problem. The proposed scheme has promising characteristics such as high computational efficiency, little required memory in the chip and low cost implementation. This method possesses all of the dynamic properties that appear in existing methods.