is a power of 2) is simply $N/2\times logN$.

Each CSTN should be paired with an RCSTN. RCSTN must be able to reverse all operations accomplished by CSTN to re-generate the plaintext. Due to the structure of CSTN, RCSTN can be implemented by *vertically flipping* the CSTN without any change in configuration [@goke1973banyan]. In fact, by vertically flipping the CSTN, and then applying the same configuration, we re-generate plaintext. So, implementing RCSTN by vertically flipping the CSTN allows us to use the same configuration for both CSTN and RCSTN. However, to avoid duplicating the hardware (to put one dedicated hardware for CSTN and one dedicated hardware for RCSTN), by flipping the configuration bits (row-pivot reversed TRN), the CSTN would operate as its corresponded reverse CSTN. Hence, only one hardware is enough to operate as both CSTN and RCSTN (using TRN or row-pivot reversed TRN).

The *OMEGA* network along with many other networks of such nature (*BUTTERFLY*, etc.) are blocking networks [@ahmadi1989survey], in which we cannot produce all permutations of input at the network’s output pins. This limitation significantly reduces the ability of a CSTN to randomize its input. Also, Evaluation of this permutation networks as a means of obfuscation to 