TLS and Energy Consumption On a Mobile Device: A Measurement Study

We report results from a measurement study on the role of the most popular end-to-end security protocol Transport Layer Security (TLS) in the energy consumption of a mobile device. We measured energy consumed by TLS transactions between a Nokia N95 and several popular Web services over WLAN and 3G network interfaces. Our detailed analysis corroborates some earlier results but also reveals, contrary to earlier studies, that the transmission and I/O energy, both in the TLS handshake and the record protocol, far exceed the required computational energy by the actual cryptographic algorithms and that with transactions larger than 500KB, the energy required to transmit the actual data clearly outranks the TLS energy overhead. In addition, we note that the energy consumption varies remarkably between measured services.