Comparison of Low-Power Implementations of Trivium and Grain

This paper provides a comparison of the two stream cipher proposals Grain and Trivium which are candidates in the hardware focus phase of the eSTREAM project. We evaluate these algorithms concerning their feasibility to implement them for low-power applications in RFID systems. A triple of parameters which includes the chip area, the power consumption, and the number of clock cycles for encrypting a fixed amount of data is introduced which allows a fair comparison of the proposals. The datapaths of the implementations are presented in detail and the synthesis results are shown. A comparison of the results of Grain and Trivium with an AES implementation shows that the chip area of Trivium is slightly smaller while Grain requires less clock cycles for encrypting 128 bits of data. The low-power implementations of the stream ciphers require only a fourth of the mean current consumption of the AES algorithm.