  The secrecy performance of realistic wireless multicast scenarios can be
significantly deteriorated by the simultaneous occurrence of multipath and
shadowing. To resolve this security threat, in this work an opportunistic
relaying-based dual-hop wireless multicast framework is proposed in which the
source dispatches confidential information to a bunch of receivers via
intermediate relays under the wiretapping attempts of multiple eavesdroppers.
Two scenarios, i.e. non-line of sight (NLOS) and line of sight (LOS)
communications along with the multiplicative and LOS shadowing are considered
where the first scenario assumes eta-mu and eta-mu/inverse Gamma (IG) composite
fading channels and the latter one follows kappa-mu and kappa-mu/IG composite
fading channels as the source to relay and relay to receiver's as well as
eavesdropper's links, respectively. Secrecy analysis is accomplished by
deriving closed-form expressions of three familiar secrecy measures i.e. secure
outage probability for multicasting, probability of non-zero secrecy multicast
capacity, and ergodic secrecy multicast capacity. We further capitalize on
those expressions to observe the effects of all system parameters which are
again corroborated via Monte-Carlo simulations. Our observations indicate that
a secrecy tradeoff between the number of relays and number of receivers,
eavesdroppers, and shadowing parameters can be established to maintain the
admissible security level by decreasing the detrimental influences of fading,
shadowing, the number of multicast receivers and eavesdroppers.
