Cryptographic Authentication for Real - Time Network Protocols 1 , 2

This paper describes a new security model and authentication scheme for distributed, real-time network protocols used in time synchronization and event scheduling applications. It outlines the design requirements of these protocols and why these requirements cannot be met using conventional cryptography and algorithms. It proposes a new design called autokey, which uses a combination of public-key cryptography and a psuedo-random sequence of one-way hash functions. Autokey has been implemented for the Network Time Protocol (NTP), but it can be adapted to other similar protocols. The paper describes the protocol operations, data structures and resources required for autokey, as well as a preliminary vulnerability assessment. AMS keywords: cryptography 94A60, data encryption 68P25