Message authentication algorithm for OFDM communication systems

With the huge expansion in the telecommunications industry, the need for robust information security is becoming more critical than ever. Physical Layer Security has, recently, emerged as a promising candidate to secure emerging communication systems in a lightweight manner. This approach has proven to be superior to existing schemes, which has motivated many researchers to shift their work towards studying, understanding and exploiting the randomness of the physical layer. In this context, this paper presents a novel keyed-hash function for Orthogonal Frequency Division Multiplexing (OFDM) systems based on the physical characteristics and properties of wireless channels. More specifically, communicating entities sharing the same channel, extract common properties and mix them with a pre-shared secret key to produce a channel-based dynamic key. This key will later be used to generate the cipher primitives needed for performing source authentication and message integrity of the transmitted OFDM symbols. Since OFDM symbols, in the frequency-domain and time-domain, have different properties, the proposed keyed-hash function is modified and adapted to suit each case leading to two variants of the solution. To the best of our knowledge, this is the first work that proposes a keyed-hash function for complex OFDM symbols, based on physical layer conditions. Finally, different security and performance tests are conducted to prove the robustness and efficiency of this technique, in comparison to currently employed message authentication schemes.