CPU Consumption Analysis of TESLA-based Navigation Message Authentication

GNSS Navigation Message Authentication (NMA) refers to the authentication of data broadcast by GNSS satellites. This authentication process requires that receivers are able to perform a significant number of cryptographic operations. These cryptographic operations are time-consuming, hence it is important to measure the computational cost of NMA operations. While GNSS receiver hardware and software implementation aspects in terms of signal processing and position computation are widely studied and optimized, this is not the case for cryptographic operations. Throughout this paper, an analysis to provide estimates about the computational cost of exploiting a NMA service based on the Timed Efficient Stream Loss-tolerant Authentication (TESLA) protocol and inserted in the Galileo OS message is presented. The performed analysis covers several platforms, user workstations and makes a special emphasis in mobile devices. The increasing number of GNSS-enabled smartphones, together with their constraints in terms of architecture, CPU and battery, makes them good candidates to analyze the impact of adding NMA to future consumer markets.