Measurement-device-independent QSDC protocol using Bell and GHZ states on quantum simulator

Abstract: Secure cryptographic protocols are indispensable for modern communication systems. It is realized through an encryption process in cryptography. In quantum cryptography, Quantum Key Distribution (QKD) is a widely popular quantum communication scheme that enables two parties to establish a shared secret key that can be used to encrypt and decrypt messages. But security loopholes still exist in this cryptographic protocol, as an eavesdropper can in principle still intercept all the ciphertext to perform cryptanalysis and the key may get leaked to the eavesdropper, although it happens very rarely. However, there exists a more secure quantum cryptographic scheme known as Quantum Secure Direct Communication (QSDC) protocol that eliminates the necessity of key, encryption and ciphertext transmission. It is a unique quantum communication scheme where secret information is transmitted directly over a quantum communication channel. We make use of measurement-device-independent (MDI) protocol in this scheme where all the measurements of quantum states during communication are performed by a third party that can be untrusted or even an eavesdropper. This eliminates all loopholes in practical measurement devices. Here, we realize this MDI-QSDC protocol using Bell and GHZ states in the IBM Quantum Experience platform and implement swapping circuits for security check.