Fig. 2

New security metrics for a simple system where the outer code is a scrambler and the inner code is a BCH(127,64) code. BER curves are given in blue with no markers, and \(\Pr \left (\hat {P}_{b}>0.5-\delta \right)\) curves are given with markers as indicated to identify the values of δ. Solid lines indicate the location is before the outer coder, while dashed lines indicate the location is after the outer coder