Contents 1 Intelligent Reflecting Surface-aided Physical-layer Security Communications -- 1.1 Overview of Physical-layer Security -- 1.2 Overview of Intelligent Reflecting Surface -- 1.3 Organization of the Monograph -- References -- 2 Enhanced Secrecy Rate Maximization for Directional Modulation Networks via IRS -- 2.1 Introduction -- 2.2 System Model -- 2.3 Proposed high-performance GAI-based Max-SR method -- 2.3.1 Optimize the beamforming vectors v1 and v2 given the IRS phase-shift matrix ���� -- 2.3.2 Optimize IRS phase-shift matrix ���� given the beamforming vectors -- 2.3.3 Overall Algorithm -- 2.4 Proposed low-complexity NSP-based Max-SR method -- 2.4.1 Optimization of beamforming vectors given IRS phase-shift matrix ���� -- 2.4.2 Optimization of IRS phase-shift matrix ���� with given beamforming vectors -- 2.4.3 Overall Algorithm -- 2.5 Simulation and Discussion -- 2.5.1 Impact of the Number of IRS Phase-shift -- 2.5.2 Impact of the IRS Location -- 2.6 Conclusion. -- References -- Contents 3 High-performance Estimation of Jamming Covariance Matrix for IRS-aided Directional Modulation Network with a Malicious Attacker -- 3.1 Introduction -- 3.2 System Model -- 3.3 Proposed Three Estimation Methods -- 3.3.1 Proposed EVD method -- 3.3.2 Proposed PEM-GD method -- 3.3.3 Proposed PEM-AO method -- 3.3.4 Computational Complexity Analysis and CRLBs -- 3.4 Simulation results and Discussions -- 3.5 Conclusion -- References -- 4 Beamforming and Power Allocation for Double-IRS-aided Two-Way Directional Modulation Network -- 4.1 Introduction -- 4.2 System Model and Problem Formulation -- 4.3 Proposed Transmit Beamforming Methods -- 4.3.1 Proposed GPG Method of Synthesizing the Phase-Shifting Matrices at Two IRSs -- 4.3.2 Proposed Max-SV Method -- 4.3.3 Generalized leakage method 4.4 Proposed HICF Power Allocation Strategy -- 4.4.1 Problem formulation -- 4.4.2 2D-ES and 1D-ES PA strategies -- 4.4.3 Proposed HICF PA strategy -- 4.5 Simulation Results andDiscussions -- 4.6 Conclusion -- 4.7 Appendix -- References -- 5 Beamforming and Transmit Power Design for Intelligent Reconfigurable Surface-aided Secure Spatial Modulation -- 5.1 Introduction -- 5.2 System Model -- 5.2.1 IRS-Aided Secure Spatial Modulation System -- 5.2.2 Problem Formulation -- 5.3 Approximation of the Ergodic Mutual Information -- 5.3.1 Traditional Approximate Secrecy Rate Expression -- 5.3.2 Proposed Newly Approximate Secrecy Rate Expression -- 5.4 Beamforming Design for given transmit power based on Approximate expression of SR -- 5.4.1 Proposed Max-NASR-SCA -- 5.4.2 Proposed Max-NASR-DA -- 5.4.3 Proposed Max-TASR-SDR method -- 5.5 Transmit Power Design for Given Beamforming based on Approximate Expression of SR -- 5.5.1 Transmit Power Design based on Proposed NASR -- 5.5.2 Transmit Power Design based on TASR -- 5.6 Complexity Analysis -- 5.7 Simulation Results and Analysis -- 5.7.1 Rayleigh fading channel -- 5.7.2 Rayleigh fading channel considering path loss -- 5.8 Conclusion -- References -- 6 IRS-Aided Covert Wireless Communications with Delay Constraint -- 6.1 Introduction -- 6.2 System Model -- 6.2.1 Considered Scenario and Assumptions -- 6.2.2 Binary Hypothesis Testing at Willie -- 6.2.3 Transmission from Alice to Bob -- 6.3 Covert Communication Design with Global Channel State Information -- 6.3.1 Optimization Problem and Perfect Covertness Condition -- 6.3.2 Joint Transmit Power and Reflect Beamforming Design -- 6.3.3 Low-Complexity Algorithm -- 6.4 Covert Communication Design without Willie's instantaneous CSI -- 6.4.1 Expression for Covertness Constraint -- 6.4.2 Optimal Design without Willie's Instantaneous CSI -- 6.5 Numerical Results -- 6.5.1 With Global CSI -- 6.5.2 Without Willie's Instantaneous CSI -- 6.6 Conclusion -- 6.7 Appendix -- 6.7.1 Proof of Theorem 6.1 -- 6.7.2 Proof of Lemma 6.1 -- 6.7.3 Proof of Theorem 6.2 -- References -- 7 Intelligent Reflecting Surface Aided Secure Transmission with Colluding Eavesdroppers -- 7.1 Introduction -- 7.2 System Model and Problem Formulation -- 7.3 Proposed Solutions -- 7.3.1 SDR-Based Method -- 7.3.2 Proposed LC-AO Algorithm -- 7.4 Simulation Results -- 7.5 Conclusion -- References -- 8 Secure Multigroup Multicast Communication Systems via Intelligent Reflecting Surface -- 8.1 Introduction -- 8.2 System Model -- 8.3 SDR-based Alternating Optimization Method -- 8.3.1 Optimization with respect to {W����, Q} -- 8.3.2 Optimization with respect to U -- 8.3.3 Overall Algorithm and Complexity Analysis -- 8.4 Low-complexity SOCP-based Algorithm -- 8.4.1 Optimization with respect to beamforming vector and AN -- 8.4.2 Optimization with respect to phase shifts -- 8.4.3 Overall Algorithm and Complexity Analysis -- 8.5 Simulation and analysis -- 8.6 Conclusion -- References -- 9 Beamforming Design for IRS-aided Decode-and-Forward Relay Wireless Network -- 9.1 Introduction -- 9.2 System Model -- 9.3 Proposed Three High-Performance Beamforming Schemes -- 9.3.1 Proposed AIS-based Max-RP Method -- 9.3.2 Proposed NSP-based Max-RP plus MRC Method -- 9.3.3 Proposed IRSES-based Max-RP plus MRC Method -- 9.4 Numerical Results -- 9.5 Conclusion -- References -- 10 Performance Analysis of Wireless Network Aided by Discrete[1]Phase-Shifter IRS -- 10.1 Introduction. -- 10.2 System Model -- 10.3 Performance Loss Derivation and Analysis in the LoS Channels -- 10.3.1 Derivation of Performance Loss in LoS Channels -- 10.3.2 Performance Loss of SNR at Bob -- 10.3.3 Performance Loss of Achievable Rate at Bob -- 10.3.4 Performance Loss of BER at Bob -- 10.4 Performance Loss Derivation and Analysis in the Rayleigh Channels -- 10.4.1 Derivation of Performance Loss in the Rayleigh Channels -- 10.4.2 Performance Loss of SNR at Bob -- 10.4.3 Performance Loss of Achievable Rate at Bob -- 10.4.4 Performance Loss of BER at Bob -- 10.5 Simulation Results and Discussions -- 10.6 Conclusion -- References -- 11 Conclusions and Future Research Directions.