In this paper, we consider a cooperative cognitive radio non-orthogonal multiple access
network, where a secondary transmitter (ST) assists transmission of a primary source-
destination (PS-PD) pair, while simultaneously communicating with a secondary receiver.
Specifically, ST acts as an untrusted relay for primary network, that overhears the primary
confidential messages. To improve the secrecy of the network, we consider a secure
transmission with friendly jamming, in which a friendly jammer transmits a jamming signal to …