On Cryptographic Algorithms and Key Length for Delayed Disclosure Authentication of GNSS

A delayed-disclosure authentication protocol aims to address Global Navigation Satellite Systems' (GNSS) vulnerability to spoofing. Cryptographic algorithms and keys are two crucial aspects of the protocol design as they have an impact on the utilized bandwidth, and therefore on the protocol performance. We first recall the latest recommendations for efficient yet secure cryptographic algorithms and key lengths. We then propose an alternative of a cryptographic algorithm and its key length that keeps the same security level while improving the computational efficiency.