Low power RC5 cipher for ZigBee portable biomedical systems

This paper presents a half-run RC5 cipher architecture with low power dissipation for transmission security of biomedical systems. The proposed architecture uses a resource-sharing approach utilizing only one adder/subtractor, one bi-directional barrel shifter, and one XOR with 32-bit bus width. Therefore, two data paths are switched through four multiplexers in the encryption/decryption procedure. A prototype chip is fabricated by a standard 0.18 μm CMOS technology. The size is 704*697 μm², where a total of 1.64k gates are used. The proposed architecture consumes 5.87 mW@50 MHz system clock.