Malicious intruders may launch as many invalid requests as possible without establishing a server connection to bring server service to a standstill. This is called a denial-of-service (DoS) or distributed DoS (DDoS) attack. Until now, there has been no complete solution to resisting a DoS/DDoS attack. Therefore, it is an important network security issue to reduce the impact of a DoS/DDoS attack. A resource-exhaustion attack on a server is one kind of denial-of-service attack. In this article we address the resource-exhaustion problem in authentication and key agreement protocols. The resource-exhaustion attack consists of both the CPU-exhaustion attack and the storage-exhaustion attack. In 2001, Hirose and Matsuura proposed an authenticated key agreement protocol (AKAP) that was the first protocol simultaneously resistant to both the CPU-exhaustion attack and the storage-exhaustion attack. However, their protocol is time-consuming for legal users in order to withstand the DoS attack. Therefore, in this paper, we propose a slight modification to the Hirose-Matsuura protocol to reduce the computation cost. Both the Hirose-Matsuura and the modified protocols provide implicit key confirmation. Also, we propose another authenticated key agreement protocol with explicit key confirmation. The new protocol requires less computation cost. Because DoS/DDoS attacks come in a variety of forms, the proposed protocols cannot fully disallow a DoS/DDoS attack. However, they reduce the effect of such an attack and thus make it more difficult for the attack to succeed.
All Science Journal Classification (ASJC) codes
- Computer Science Applications
- Computer Networks and Communications