Enhancing the Oakley key agreement protocol with secure time information

Message freshness and time synchronization are nowadays essential services in secure communication. Many network protocols can work correctly only when freshness of messages sent between participants is assured and when internal clocks protocol's parties are adjusted. In this paper we present a novel, secure and fast procedure which can be used to ensure data freshness and clock synchronization between two communicating parties. Next, we show how this solution can be used in cryptographic protocols. As an example we apply our approach to the Oakley key determination protocol providing it with time synchronization without any additional communication overhead.