2021/11/29 by Shayan Mohajer Hamidi, Hamidi, Shayan Mohajer, Amir K. Khandani +3
Computer Science · Engineering · #Chaos-based Image/Signal Encryption #Cooperative Communication and Network Coding #FOS: Computer and information sciences #FOS: Electrical engineering #Information Theory (cs.IT) #Signal Processing (eess.SP) #Wireless Communication Security Techniques #electronic engineering #graph theory and CDMA systems #information engineering
paper · pdf · doi:10.48550/arxiv.2111.15046
openalex publication_date 2021/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
This article presents a secure key exchange algorithm that exploits reciprocity in wireless channels to share a secret key between two nodes A and B. Reciprocity implies that the channel phases in the links A→ B and B→ A are the same. A number of such reciprocal phase values are measured at nodes A and B, called shared phase values hereafter. Each shared phase value is used to mask points of a Phase Shift Keying (PSK) constellation. Masking is achieved by rotating each PSK constellation with a shared phase value. Rotation of constellation is equivalent to adding phases modulo-2π, and as the channel phase is uniformly distributed in [0,2π), the result of summation conveys zero information about summands. To enlarge the key size over a static or slow fading channel, the Radio Frequency (RF) propagation path is perturbed to create several independent realizations of multi-path fading, each used to share a new phase value. To eavesdrop a phase value shared in this manner, the Eavesdropper (Eve) will always face an under-determined system of linear equations which will not reveal any useful information about its actual solution value. This property is used to establish a secure key between two legitimate users.