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sec TBD RFC Request for Comments I-D Internet-Draft TESLA This document updates TESLA to current cryptographic methods for use by the International Civil Aviation Organization (ICAO) in their Global Navigation Satellite System (GNSS) Satellite-based augmentation system (SBAS) authentication protocol. The TESLA updates are to align it with current best practices.

Introduction TESLA (Timed Efficient Stream Loss-Tolerant Authentication) uses the best practices for cryptography when published in 2005. This is quite dated, and any modern use of TESLA needs to adjust to current algorithms and methods. This document focuses on thhe TESLA design targeted by the International Civil Aviation Organization (ICAO) in their Global Navigation Satellite System (GNSS) Satellite-based augmentation system (SBAS) authentication protocol. The SBAS authentication protocol is more than a modern TESLA implementation. It uses a very tightly designed PKI and the C509 certificate encoding to work within the very highly constrained SBAS communication link. The PKI is out-of-scope for this document and is described elsewhere within ICAO. This document is very much a "work in progress", in that various ICAO SBAS documents need to be excised for their technical updates to TESLA. For example, TESLA specifies using a message authentication code (MAC) of all communicated data. SBAS is using HMAC and KMAC .

SBAS use of TESLA The updating of TESLA in SBAS Authentication is outlined in . This document is the public source of changes made to TESLA and some of the justifications.

Terms and Definitions

Requirements Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

Updates to TESLA TBD - extracted from SBAS documents.

IANA Considerations TBD

Security Considerations TBD

References Journal of the Institute of Navigation

Acknowledgments This work is in conjunction with the ICAO SBAS Authention Study Group members. This includes, and is not limited to: Jed Dennis (FAA Consultant), Abdel Youssouf (Eurocontrol), Timo Warns (Airbus), Todd Walter (Stanford) and chair Mikaël Mabilleau (Eurocontrol).