A Study on Secret Key Extraction System Based on the Reciprocity of Channel

임상훈, Sanghun Im

Xiaohua Wu, Chunjing Hu, Yuexing Peng +2 more

Channel reciprocity is limited in frequency division duplex (FDD) system, and thus those channel reciprocity-based secret key extraction methods which are widely adopted in time division duplex (TDD) systems can hardly be implemented in FDD systems. In this paper, a novel secret key extraction method in OFDM-FDD system is proposed to achieve physical-layer security, by which the channel frequency response (CFR) in the uplink at the same time is estimated by the communication pair with the aid of a specially designed forwarding strategy based on confidential probing signal, and then the secret key is extracted from the CFR estimates. The effectiveness of the proposed method is verified by numerical simulations.

Zhi Wang, Jinsong Han, Wei Xi +1 more

Chandni Akbar, Hassan Mahmood, Qurratul-Ain Minhas +1 more

Now-a-days, secure communication is a significant characteristic that should be proficient to accommodate increasing demand of wireless communication. The fundamental principle of secure communication is the extraction of secret key and keeping this secret. In this paper, we propose innovative approach for secret key extraction and reconciliation. We exploit channel reciprocity through relative calibration and use this reciprocal channel as a secret key between two legitimate users. In this method, there is no physical sharing of key between users so that eavesdropper could not interfere the confidential communication. We also prove that this algorithm is more secure as compare to other algorithms. We use AES algorithm for reconciliation of secret key for secure communication.

Haji Muhammad Furqan, Jehad M. Hamamreh, Hüseyin Arslan

The generation of secret keys from reciprocal wireless channel by exploiting their randomness nature, is an emerging area of interest to provide secure communication. One of the main challenges in this domain is to increase the secret key length, extracted from the shared channel coefficients between two legitimate communication parties, while maintaining its randomness and uniformity. In this work, we develop a practical key generation method, based on channel quantization with singular value decomposition (CQSVD), which is capable of significantly increasing the generated secret key in MIMO systems. This is achieved through quantizing the phases and amplitudes of the estimated MIMO channel coefficient's matrix by using an alternative form of SVD, where the key sequence is extracted from the orthogonal basis functions of the decomposed channel. In this method, it is shown that for an M ×M antenna system, with M2independent channel fading coefficients, a secret key sequence of length 2M3can be generated. The extracted key sequence is transformed to a random phase sequence, which is then used to manipulate the transmitted data on a symbol level basis rather than bit level-basis, to provide more secure communication. The comparative simulation results show that the proposed CQSVD method outperforms the state of the art secret key generation methods.

Tijana Radojević