Filter Design With Secrecy Constraints: The Degraded Parallel Gaussian Wiretap Channel

The authors introduce the problem of filter design with secrecy constraints in the classical wiretap scenario, where two legitimate parties, Alice and Bob, communicate in the presence of an eavesdropper, Eve. In particular, they consider the design of transmit and receive filters that minimize the Mean-Squared Error (MSE) between the legitimate parties whilst guaranteeing a certain eavesdropper MSE level subject to a total average power constraint, in the situation where the main channel and the wiretap channel consist of a bank of parallel independent degraded Gaussian channels (a scenario representative of Orthogonal Frequency Division Multiplexing (OFDM) communications systems).