Properties of the RC6 cipher for a BIST hardware implementation

In 1997, the National Institute of Standards and Technology (NIST) initiated a process to select a symmetric-key encryption algorithm to be used to protect sensitive federal information. From the fifteen candidate algorithms, six were selected. One of them is the RC6 cipher-block. In this paper we make an analysis of suitability for pseudorandom built-in self-test (BIST) of the RC6 algorithm. First, we describe the hardware architecture, based on the architecture data flow graph. To prove that each combinational level has by entrance a pseudo-random data, we show that the order of the involved operations and the operation type are relevant, and not the number of instances of a certain operation. Also we prove the random data property of RC6 and some important properties of the cipher that permits the implementation of an efficient BIST scheme to test the complete data path.