The globalization of semiconductor supply chains has exposed Network-on-Chip (NoC) interconnects in System-on-Chip (SoC) architectures to critical security risks, including reverse engineering and IP theft. To address these threats, this work builds on two methodologies: ObNoCs [11], which obfuscates NoC topologies using programmable multiplexers, and POTENT [10], which enhances post-synthesis security against SAT-based attacks. These techniques ensure robust protection of NoC interconnects with minimal performance overhead. As the industry shifts to chiplet-based heterogeneous architectures, this research extends ObNoCs and POTENT to secure intra- and inter-chiplet interconnects. New challenges, such as safeguarding inter-chiplet communication and interposer design, are addressed through enhanced obfuscation, authentication, and encryption mechanisms. Experimental results demonstrate the practicality of these approaches for high-security applications, ensuring trust and reliability in monolithic and modular systems.