  Symmetric encryption has been a standout amongst the most reliable option by
which security is accomplished. In modern block symmetric ciphers, the
substitution-boxes have been playing a critical role of nonlinear components
that drives the actual security of ciphers. In this paper, the travelling
salesman problem and piecewise linear chaotic map are explored to synthesize an
efficient configuration of 8x8 substitution-box. The proposed anticipated
design has the consistency which is justified by the standard performance
indexes. The statistical results manifest that the prospective substitution-box
is cryptographically more impressive as compared to some recent investigations.
