We analyze the computation overhead of the IP security protocol (IPSec) on a handheld device. We design experiments to quantify the energy consumed by the individual components in IPSec. We then experiment with several measures which can potentially cut the energy consumption without compromising security. Our results show that by replacing 3DES with Advanced Encryption Standard as the encryption algorithm, the total energy consumption is reduced by up to 38%. On the other hand, MD5 and SHA-1 consume about the same amount of energy for message authentication, which makes SHA-1 more preferred because of its known higher strength against birthday attacks. We also find that the power-saving mode of the wireless LAN interface does not reduce (and may even increase) the total energy cost despite the substantial amount of network idle time. Finally, we find that the data compression option must be used carefully. When sending data from the handheld device, the lossless compression used in IPSec can actually increase the energy consumption until the network bandwidth drops down to 2 Mbps or lower. However, compression is found to save energy when the device receives compressible data under normal bandwidths. This result suggests that the compression option must be dynamically changed in IPSec between data transmission and reception.
['Peifeng Ni', 'Zhiyuan Li']
Energy cost analysis of IPSec on handheld devices