Atbash cipher design for secure nanocommunication using QCA

Quantum dot cellular automata (QCA) are a rising paradigm at the nanotechnology level that seems to be an alternative solution to complementary metal–oxide–semiconductor circuits. QCA have high device density, high switching speed and extremely low power consumption. The hardware architecture of cryptographic systems is a major issue in terms of power dissipation and circuit density in formulating secure nanocomputing channels. Cryptography can be the most promising application of QCA, which has not yet been much explored. This paper describes the design of the Atbash cipher in QCA for the first time. The proposed design requires only a 0·223 µm² area, six majority gates, nine inverters and four clocking zones and has a latency of 1·25. The proposed circuit consumes very little power and thus can be resistant to power analysis attack against communication networks. During implementation, several issues such as clocking and device density are considered. To evaluate the circuit, an 8-bit sequence of data – that is, 1-byte stream of data – of plain text at a time is used as an input to the proposed circuit. The comparison of simulation results with theoretical knowledge confirms the functional efficiency of the circuit.