Physical layer secret key generation is a promising candidate to achieve one-time-pad encryption approach for wireless communication system. The main issue of this method is the insufficient secret key rate. Especially in a static environment, the entropy of the channel complex coefficient is limited due to the lack of channel time-variation. To solve the problem, this paper proposes a novel secret key generation scheme assisted by intelligent reflecting surface (IRS) with discrete phase. We construct a dynamic time-varying channel by switching the phase of the reflection elements rapidly and randomly, and use channel estimation samples to update the secret key. Based on the common IRS channel model, we derive the expression of secret key rate. Monte Carlo simulation and numerical results show that the scheme can update secret key even if the channel coefficient is constant, and the secret key rate is higher than schemes based on artificial random signal. In addition, we comprehensively analyze the influence of various factors, such as the number of reflection elements and the IRS switching frequency on the secret key rate.

This paper proposes a novel physical layer one-time pad (OTP) encryption scheme for modulated signals based on the wireless channel. By imitating the OTP encryption for bit sequence, the sufficient conditions of perfect encryption for modulated signals are provided and proved. Then, we provide a detailed process of the scheme in the wireless system. Since the plaintext is the modulated signal rather than the bit sequence, we use high-level quantized channel estimation samples as secret keys and design encryption functions for QAM and PSK signals. The theoretical proof and Monte Carlo simulation results show that the proposed scheme can achieve perfect secrecy by designing the ciphertext signal independent of the plaintext signal. Furthermore, the simulation shows that the error probability of the proposed scheme is lower than that of the current mainstream physical layer encryption scheme because  the quantization level is optimized according to the signal-to noise ratio.

In this paper, we propose a conjecture that endogenous security without any prior knowledge is similar to perfect secrecy without any prior knowledge. To prove the conjecture, we first establish a cryptography model of instinct function security to transform the security problem in the network domain into an encryption problem in the cryptographic domain. Then, we inherit and apply the established ideas and means of the Perfect Secrecy, and propose the concept, definition and corollaries of the perfect instinct function security (PIFS) corresponding to the Perfect Secrecy. Furthermore, we take the DHR system as a concrete implementation of PIFS and propose the DHR Perfect Security Theorem corresponding to Shannon’s Perfect Secrecy Theorem. Finally, we prove that the DHR satisfying the “One-Time Reconstruction” constraint is the sufficient and necessary condition to achieve perfect security. This means that the existence of PIFS is also proven. The analysis shows that any reconfigurable system can be encrypted by its construct and that the PIFS converts the one-way transparent superiority of the attacker into a double-blind problem for both the attacker and the defender, which leads to that the attacker is impossible to obtain useful construction information from the attacks and unable to find a better way than blind trial-and-error or brute-force attacks. Since the attackers are required to have the new powerful ability to crack the structure cryptogram, the threshold of cyber security is raised to at least the same level as cryptogram deciphering, thereafter the ubiquitous cyber threats are destined to be significantly reduced.

Abstract: The information security and functional safety of wireless communication systems have become the focus of current research. The endogenous security principle based on Dynamic Heterogeneous Redundancy provides a direction for the development of wireless communication security and safety technology. This paper introduces the concept of wireless endogenous security from the following four aspects. First, we sorts out the endogenous security problems faced by the current wireless communication system, and then analyzes the endogenous security and safety attributes of the wireless channel. After that, the endogenous security and safety structure of the wireless communication system is given, and finally the applications of the existing wireless communication endogenous security and safety functions are listed.