The widespread rollout of fifth-generation (5G) wireless systems has delivered extremely low latency, extensive device interconnectivity, and enhanced data transmission rates. However, it has also introduced significant security concerns due to virtualization, diverse network structures, and expanded attack vectors. Protecting data in such environments demands cryptographic techniques that are both secure and resource-efficient. This study proposes a secure communication framework for 5G networks using optimized cryptographic methods to ensure confidentiality, integrity, and authentication while maintaining system performance. The framework combines lightweight encryption techniques, efficient key distribution strategies, and adaptive security configurations suited to various 5G use cases such as enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC). Performance analysis is carried out based on metrics including processing cost, delay, throughput, and security robustness. The findings indicate that the proposed method lowers encryption overhead while effectively defending against common threats like eavesdropping, replay, and man-in-the-middle attacks. Overall, the framework provides a scalable and efficient approach for securing future 5G wireless communication systems.