The increasing growth of digital schemes will lead to safer and tamper-resistant electronic components. Software solutions, all too common when it comes to security, are often inadequate to counter the well-equipped cyber criminals. This demonstrates an increasing need for security based on hardware. Nanomaterials have become central to these security applications because of their unique structural, electronic and optical properties. This chapter explores the role of nanomaterials in cybersecurity, from traditional encryption mechanisms to hardware-related security components, including physically unclonable functions (PUFs) and true random number generators (TRNGs). The chapter examines manufacturing methods and demonstrates the role of nanoscale properties—structural disorder, defect density and tunable properties—in determining the performance and reliability of a device. The chapter considers a number of important applications in cryptographic systems, anticounterfeiting, and electromagnetic interference shielding, as well as designs for trustworthy hardware, demonstrating their relevance in both industrial and social contexts. Key barriers relating to scalability, consistency, systems integration and long-term reliability have all been evaluated. Finally, the discussion on future trends, including composite nanostructures and new manufacturing methods, highlights a vision for nanomaterials to transform secure electronic systems of the future.