ARQ Secrecy: From Theory to Practice

Keys through ARQ: Theory and Practice

This paper develops a novel framework for sharing secret keys using the Automatic Repeat reQuest (ARQ) protocol. We first characterize the underlying information theoretic limits, under different assumptions on the channel spatial and temporal correlation function. Our analysis reveals a novel role of "dumb antennas" in overcoming the negative impact of spatial correlation on the achievable secrecy rates. We further develop an adaptive rate allocation policy, which achieves higher secrecy rates in temporally correlated channels, and explicit constructions for ARQ secrecy coding that enjoy low …

Keys through ARQ

This paper develops a novel framework for sharing secret keys using the well-known Automatic Repeat reQuest (ARQ) protocol. The proposed key sharing protocol does not assume any prior knowledge about the channel state information (CSI), but, harnesses the available opportunistic secrecy gains using only the one bit feedback, in the form of ACK/NACK. The distribution of key bits among multiple ARQ epochs, in our approach, allows for mitigating the secrecy outage phenomenon observed in earlier works. We characterize the information theoretic limits of the proposed scheme, under different assumpt…

高斯块衰落信道下安全混合ARQ协议的性能研究

On the Throughput of Secure Hybrid-ARQ Protocols for Gaussian Block-Fading Channels

本文的重点是一个信息理论研究的可靠的数据包通信的重传协议下的保密性约束。重新访问的混合自动重传请求（HARQ）协议的块衰落窃听信道，其中两个合法的用户在块衰落信道中的存在下，一个被动的窃听者拦截的传输通过一个独立的块衰落信道进行通信。在该模型中，发射机经由无差错公共信道从合法接收机获得1比特ACK/NACK反馈。通过联合考虑信道编码、保密编码和重传协议，研究了安全HARQ协议的可靠性和保密性。特别是，基于良好的Wyner码序列的重复时间分集（RTD）和增量冗余（INR）协议的错误和保密性能进行了研究，这确保了机密消息被成功解码的合法接收机，并保持在一个给定的信道实现集的窃听者完全无知。本文首先说明了存在一个良好的速率兼容的Wyner码族，确保安全的INR协议。接下来，两种类型的中断概率，连接中断和保密中断概率的定义，以表征合法通信链路的可靠性和相对于窃听者的链路的机密性之间的权衡。对于一个给定的连接/保密中断概率对，安全HARQ协议的可实现的吞吐量块衰落信道。最后，渐近分析和数值计算表明HARQ协议的吞吐量和保密性的好处。

Achieving the Secrecy Capacity of Wiretap Channels Using Polar Codes

Suppose Alice wishes to send messages to Bob through a communication channel C_1, but her transmissions also reach an eavesdropper Eve through another channel C_2. The goal is to design a coding scheme that makes it possible for Alice to communicate both reliably and securely. Reliability is measured in terms of Bob's probability of error in recovering the message, while security is measured in terms of Eve's equivocation ratio. Wyner showed that the situation is characterized by a single constant C_s, called the secrecy capacity, which has the following meaning: for all $ε> 0$, there exist co…

Securing NOMA Networks by Exploiting Intelligent Reflecting Surface

This paper investigates the security enhancement of an intelligent reflecting surface (IRS) assisted non-orthogonal multiple access (NOMA) network, where a distributed IRS enabled NOMA transmission framework is proposed to serve users securely in the presence of a passive eavesdropper. Considering that eavesdropper's instantaneous channel state information (CSI) is challenging to acquire in practice, we utilize secrecy outage probability (SOP) as the security metric. A problem of maximizing the minimum secrecy rate among users, subject to the successive interference cancellation (SIC) decoding…

Reconfiguring Wireless Environment via Intelligent Surfaces for 6G: Reflection, Modulation, and Security

Reconfigurable intelligent surface (RIS) has been recognized as an essential enabling technique for the sixth-generation (6G) mobile communication network. Specifically, an RIS is comprised of a large number of small and low-cost reflecting elements whose parameters are dynamically adjustable with a programmable controller. Each of these elements can effectively reflect a phase-shifted version of the incident electromagnetic wave. By adjusting the wave phases in real time, the propagation environment of the reflected signals can be dynamically reconfigured to enhance communication reliability,…