This study explores the secrecy rate of a new system model comprising a control jamming-enabled simultaneous transmission and reflection reconfigurable intelligent surfaces (STAR-RIS) in a non-orthogonal multiple access (NOMA) downlink network. The study considers non-ideal hardware defects (HWDs) at the transceivers, particularly when the direct links from the source node (S) to the NOMA users \(\left( U_{r},U_{t}\right) \) are blocked. The STAR-RIS, employing the energy splitting protocol, serves two users located on opposite sides of the STAR-RIS structure, allowing simultaneous eavesdropping. The introduction of a control jammer enhances security and is assessed in various scenarios, including without jamming (WJ), with jamming (J), and control jamming (CJ), for both the transmitting user \(\left( U_{t}\right) \) and the reflecting user \(\left( U_{r}\right) \) . To augment security, an optimization problem is formulated with a total power constraint, optimizing power allocation at both users. This problem is iteratively addressed using the Lagrange multiplier method (LMM) and Particle Swarm Optimization-based power allocation (PSO-PA) method. Performance analysis compares the recommended PSO-PA scheme, LMM technique, and constant power allocation scheme in terms of secrecy rate under various jamming scenarios (WJ, J, and CJ). Additionally, the impact of statistical parameters like signal-to-noise ratio, number of STAR elements, and non-ideal HWDs on secrecy rate is examined using the CJ technique at both NOMA users.
