8-bit-microcontroller system with area efficient AES coprocessor for transponder applications

Apart from pure identification systems, transponder systems with embedded sensors gain increasing importance. In contrast to low-end Radio Frequency Identification (RFID) systems these transponders usually require more complex protocols which need to be adjusted to a specific application. In this contribution the demanded flexibility is achieved by using the 8-bit-microcontroller IMS3311. In order to guarantee privacy and security of transferred information, it is essential that transmitted data is encrypted by a strong algorithm. Therefore, the Advanced Encryption Standard (AES) is used. The main focus of this paper is the development of an area-efficient AES coprocessor which accelerates the processing of the controller's ciphering tasks. The AES unit requires only 2168 logic gates and takes less than 650 clock cycles for either encryption or decryption of a 128-bit block.