Efficient message authentication for spread spectrum wireless communications

In this paper, we present a new scheme to reduce the communications requirements to send message authentication tags (MAC´s), by sending the MAC´s over direct sequence spread spectrum wireless channels. We greatly reduce the number of chips required by considering the chip sequence as a whole. In one example, based on the IS-95 CDMA digital cellular standard, we reduce the chips needed from 3072 to 1142 by a hard decision decoding scheme, and to 728 by a soft decision decoding scheme, achieving savings of factors about three and four, respectively.