en 2-VLSI VLSI Research Paper Research Paper <span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">CMOS technology, after contributing a lot to electronics world, is now facing difficulties in designing of more efficient circuits in terms of compactness, power efficiency and speed. It is happening due to various side effects being generated on account of further down scaling of feature size. The Quantum Dot Cellular Automata (QCA) technology seems to be alternate and promising technology for designing of more efficient circuits. The cryptographic encoder and decoder are the key component for secure and safe communication. This paper presents an efficient design of 1:2 demultiplexer, 1:4 demultiplexer and 4:1 multiplexer which are further used to design a cryptographic nano communication circuit. The proposed circuits are efficient in terms of energy, area and speed. The architectures are designed through multilayer approach in QCA technology that makes it compact. The efficiency of the proposed circuits has been verified through the tool QCA Designer 2.0.3.</span></span> Quantum Dot Cellular Automata, multiplexer, demultiplexer, multilayer design, cryptographic architecture, nano communication. 136 149 http://ijeee.iust.ac.ir/browse.php?a_code=A-10-4705-1&slc_lang=en&sid=1 Paramjeet . chauhan.paramjeet@gmail.com 1800319475328460017726 1800319475328460017726 No Department of Electronics and Communication Engineering, Faculty of Engineering and Technology, SRM Institute of Science and Technology, Delhi-NCR Campus, Modinagar, Ghaziabad 201204, U.P., India. Saptarshi Gupta ece.saptarshi@gmail.com 1800319475328460017727 1800319475328460017727 Yes Department of Electronics and Communication Engineering, Faculty of Engineering and Technology, SRM Institute of Science and Technology, Delhi-NCR Campus, Modinagar, Ghaziabad 201204, U.P., India. Rupali Singh rupal.rishi@gmail.com 1800319475328460017728 1800319475328460017728 No Department of Electronics and Communication Engineering, Faculty of Engineering and Technology, SRM Institute of Science and Technology, Delhi-NCR Campus, Modinagar, Ghaziabad 201204, U.P., India.