tokens: Specifically , in this work , three key contributions are reported : ( 1 ) 5 G IoT enabled secure audio - visual hearing - aid framework that aims to achieve a round - trip latency up to 5ms with 100 Mbps datarate ( 2 ) Real - time lightweight audio - visual encryption based on piece - wise linear chaotic map ( PWLCM ) , chebyshev map , secure hash , and a novel substitution box ( S - Box ) algorithms ( 3 ) Lip - reading driven deep learning approach for speech enhancement in the cloud .