An Improved Key-Agreement Protocol for Channels with Small Error Rate

Abstract

Symmetric cryptosystems are very important for secure communication. They are much more efficient then asymmetric cryptosystems. Secret keys are required for symmetric cryptosystems, such as AES. In 2017, Guan and Tzeng designed a secret key establishment protocol whose security depends on the unpredictability of noise in communication channel. They showed that these protocols are secure even if the eavesdropper has infinite computing power. Their protocol works most efficiently for channels with bit-flip rate around 0.01. For the case when bit-flip rate is much smaller than 0.01, their protocol needs a long random bit string to accumulate enough uncertainty to establish a secret key. In this article, an improved protocol for establishing secret key is proposed. The new method requires much less random bits for channels with small bit-flip rates, such as in the range [0.001, 0.010]. With the improvement of wireless communication technology, the bit-flip rate is reducing. Therefore, the new method is suitable for the current wireless networks technology.