An over-the-air key establishment protocol using keyless cryptography

Today, an increasing number of devices wirelessly communicate with each other. However, due to the nature of wireless transmission, the communications are vulnerable to many adversarial attacks such as eavesdropping. Key establishment is one of the fundamental and widely studied countermeasures for securing the communications. In certain applications, the wireless devices may be energy-constrained, such as sensor nodes. Thus, energy intensive asymmetric key establishment protocols are infeasible. Additionally, in some scenarios, it is not practical to assume that all the devices pre-share certain secrets. Motivated by these observations, this paper presents an over-the-air key establishment protocol using keyless cryptography. Specifically, the proposed protocol is designed without using asymmetric key cryptography and pre-shared secrets. More specifically, our protocol provides a concrete construction to transform the wireless channel into an anonymous channel, and two wireless devices can establish a secret key by directly sending random signals to each other. The performance analysis shows that the energy consumption of our protocol is around 176 times cheaper than that of the Diffie-Hellman key exchange protocol. Additionally, it takes only 159.04 ms to establish a key with 112 secret bits.