  In this paper, we consider multiple cache-enabled end-users connected to
multiple transmitters through a linear network. We also prevent a totally
passive eavesdropper, who sniffs the packets in the delivery phase, from
obtaining any information about the original files in cache-aided networks.
Three different secure centralized multi-transmitter coded caching scenarios
namely, secure multi-transmitter coded caching, secure multi-transmitter coded
caching with reduced subpacketization, and secure multi-transmitter coded
caching with reduced feedback, are considered and closed-form coding delay and
secret shared key storage expressions are provided. As our security guarantee,
we show that the delivery phase does not reveal any information to the
eavesdropper using the mutual information metric. Moreover, we investigate the
secure decentralized multi-transmitter coded caching scenario, in which there
is no cooperation between the clients and transmitters during the cache content
placement phase and study its performance compared to the centralized scheme.
We analyze the system's performance in terms of Coding Delay and guarantee the
security of our presented schemes using the Mutual Information metric.
Numerical evaluations verify that security incurs a negligible cost in terms of
memory usage when the number of files and users are scaled up, in both
centralized and decentralized scenarios. Also, we numerically show that by
increasing the number of files and users, the secure coding delay of
centralized and decentralized schemes became asymptotically equal.
