Satellite communication networks have been widely used to provide essential communication services, including voice communication, global positioning, message communication, etc. However, sorts of network attacks are easy to be launched in these networks due to the limited computation capability and communication width, long communication delay, and intermittent link connection. In this paper, we first propose a new [E]ncryption-based [M]utual [A]uthentication and [K]ey [U]pdate (EMAKU) protocol in satellite communication networks. Next we analyze the security of the EMAKU protocol under two classic network attacks which are replay attack and man-in-the-middle attack. Finally, experiments show that the EMAKU protocol is 21.5% faster than the traditional encryption-based authentication protocols, and the average time of key update of the EMAKU protocol is about 450.01 ms.
