Analysis and Recommendations for MAC and Key Lengths in Delayed Disclosure GNSS Authentication Protocols

Data and signal authentication schemes are being proposed to address Global Navigation Satellite Systems' (GNSS) vulnerability spoofing. Due the low power of their signals, bandwidth available for in GNSS is scarce. Since delayed-disclosure protocols, e.g., TESLA (timed-efficient stream loss-tolerant authentication), efficient terms robust impairments, they have been implemented by GNSS. The length message codes (MACs) cryptographic keys two crucial aspects protocol design as an impact on utilized bandwidth, therefore performance. We analyze both detail GNSS-TESLA present recommendations yet safe MAC key lengths. further complement this analysis proposing possible success failure policies quantify reduction attack surface resulting from employing them. shows that some cases it use sizes smaller than those best-practice guidelines. While our considerations general lightweight protocols data authentication, we particularize them protocols.