Quantum Cryptography Experiment using Optical Devices

Abstract

The study of quantum cryptography is one of the great interest. A straightforward and reliable quantum experiment is provided in this paper. A half wave plate in linearly polarized light makes up a simplified polarization rotator. The polarization rotates twice as much as the half wave plate's fast axis' angle with the polarization plane when the half wave plate is rotated. Here, an experiment of message sharing is conducted to demonstrate quantum communication between parties. The unitary transformation is performed step by step using half-wave plates represented by the Mueller matrix. A simulation created using Python programming has been used to test the proposed protocol's implementation. Python was chosen because it can mathematically imitate the quantum state of superposition.

Performance Analysis for Secret Message Sharing using Different Levels of Encoding Over QSDC

“…The tested bit size for the comparing multiphoton approaches was 10. For each of the analyzed protocols, the time to convey a small amount of information and the time it takes the half-wave plate to rotate from its initial position to its new position is taken from previous studies [22]. Every eight bits, the half wave plate's update angle or rotation is changed for authentication purposes.…”

“…Three steps are involved in the suggested approach which are the encoding, transformation and decoding stages. The suggested protocol has been discussed in detail based on an experiment conducted by Azahari et al [22]:…”

“…Faster transmission times result from increased bit capacity whenever the encoding level is raised. Therefore, it is believed that the transmission process as a whole will significantly improve [22]. Total transmission time includes the time required by HWP to change angles for the transmission of 8 bits of information, which is represented by 𝑇 𝐻𝑊𝑃 , as well as the time required for multiphoton transmission through a quantum communication channel, which is 𝑇 𝑚𝑠𝑔 .…”

Protocol Efficiency Using Multiple Level Encoding in Quantum Secure Direct Communication Protocol

“…The time to transmit a small amount of information and the time it takes the HWP to rotate from its original position to its new position for each of the procedures under analysis are taken from earlier studies. For authentication, the update angle or rotation of the HWP is changed every eight bits [20]. Although it takes longer to transfer the information, the fast polarisation changes have increased the level of security.…”

“…At this stage, the beam is directed towards the HWP in order to change its polarisation using a secret polarisation angle. The HWP is updated for each batch of bits and is oriented at a specific angle [20].…”