This paper investigates the security performance of two relay selection schemes for cooperative non-orthogonal multiple access (NOMA) systems. where K randomly distributed relays are employed with either decode-and-forward (DF) or amplify-and-forward (AF) protocols. More particularly. two-stage relay selection (TRS) and optimal relay selection (ORS) schemes are taken into consideration. https://oxfordshopes.shop/product-category/knitwear-urban-cardigan/