Data protection using recursive inverse function

Teng Xu, Hongxiang Gu, Miodrag Potkonjak

Abstract: Data security and privacy have emerged to become an important issue in various types of applications. Although many cryptographic cyphers are proposed to leverage the issue, they normally suffer from the problems of either requiring large power/bandwidth consumption or employing linear system which is easy to break. To solve the problem of traditional cyphers, we have proposed a new hardware security primitive: recursive inverse function (RIF) designed on the field-programmable gate array (FPGA). The RIF takes advantage of a pair of inverse functions, building a recursive scheme for message encryption and decryption. The inverse functions are defined as a pair of functions where each function implements a mapping being inverse to the mapping of the other function. On the top of it, the recursive structure guarantees the input-output mapping to be statistically extremely hard to predict. The RIF can be easily implemented using hierarchical lookup-table (LUT) structures with low delay and power overhead. Using our proposed RIF structure, we have demonstrated how the RIF can be incorporated into a processor design to enable the data protection. Finally, we implement our scheme on a Xilinx Spartan-6 FPGA device to analyze the performance and the overhead.