Quantum secure direct communication (QSDC) is a branch of quantum cryptography which exploits laws of physics and was recently proposed for securing information transferred from sender to receiver without relying on computational complexity. Instead of an entangled photon, the quantum cryptography employs two other approaches, single photon and multiphoton for encoding the messages. The multiphoton was proposed to outperform the weaknesses of a single photon by introducing the multiplicity of a photon to perform data encryption tasks. Despite the advantages of multiphoton, the transmission time to transfer the encoded data is still regarded as a critical issue. Most of the multiphoton approaches require multiple photons to travel along a number of stages. Moreover, extra time is needed to change the polarization angle of the optical device for encoding purposes. These situations have resulted in an increase in source redundancy, which subsequently leads to an increase in the transmission time. In this paper, a compression message approach is proposed to mitigate the substantial increase in time used for the data transmission processes. The proposed compression approach, namely, hybrid M-ary in a braided single stage (HMBSS) is based on the lossless data encoding such that the number of photons is reduced in the data transmission stage. Extensive simulation experiments have been conducted to test the performance of the proposed approach against some selected multiphoton approaches. The results show that the proposed approach outperforms braided single-stage, M-ary three-stage and initialization vector in terms of reducing total average transmission time to encode the photon by about 75.9% and 91.7%, respectively. Furthermore, the HMBSS reduces the overhead on the transmission channel by minimizing the number of message's bits by about 45% in average even when the length of the message increases during the transmission as compared to others.
Quantum secure direct communication (QSDC) is a branch of quantum cryptography which exploits laws of physics and was recently proposed for securing information transferred from sender to receiver without relying on computational complexity. Instead of an entangled photon, the quantum cryptography employs two other approaches, single photon and multiphoton for encoding the messages. The multiphoton was proposed to outperform the weaknesses of a single photon by introducing the multiplicity of a photon to perform data encryption tasks. Despite the advantages of multiphoton, the transmission time to transfer the encoded data is still regarded as a critical issue. Most of the multiphoton approaches require multiple photons to travel along a number of stages. Moreover, extra time is needed to change the polarization angle of the optical device for encoding purposes. These situations have resulted in an increase in source redundancy, which subsequently leads to an increase in the transmission time. In this paper, a compression message approach is proposed to mitigate the substantial increase in time used for the data transmission processes. The proposed compression approach, namely, hybrid M-ary in a braided single stage (HMBSS) is based on the lossless data encoding such that the number of photons is reduced in the data transmission stage. Extensive simulation experiments have been conducted to test the performance of the proposed approach against some selected multiphoton approaches. The results show that the proposed approach outperforms braided single-stage, M-ary three-stage and initialization vector in terms of reducing total average transmission time to encode the photon by about 75.9% and 91.7%, respectively. Furthermore, the HMBSS reduces the overhead on the transmission channel by minimizing the number of message's bits by about 45% in average even when the length of the message increases during the transmission as compared to others.
In order to mitigate the problem of low transmission rate and limited communication distance in Quantum Communication (QCs), multiphoton over multi-stages approach has been proven to be a possible alternative to the conventional single photon approach. Multiphoton has the ability to improve the range of distances and key generation rate over multi-stages photon transmission. However, the determination of optimal mean photon numbers and number of stages in multiphoton approach remains a key challenge to make the protocols well utilized during their operations. Following this concern, three problems and their corresponding proposed solutions in this thesis are presented below: Firstly, the existing multiphoton approaches involve multiple photons to travel throughout a number of stage. Furthermore, extra time is required to update the polarization angle of optical device for encoding purposes. These conditions would result in an increase in the total transmission time of the photons to be transmitted over the quantum channel. Accordingly, a Hybrid M-Ary in Braided Single-Stage (HMBSS) approach by utilizing data compression concept is proposed to address these issues. In HMBSS, the sender is able to compress the secret message using Huffman encoding over the braided single-stage operation. This compression mechanism has reduced the number of bits required to represent a string of symbols, thereby reducing the time to encode the photons. The simulation experiments shows that HMBSS achieved promising result by 75.9% and 91.7% total average transmission time decrease as compared to the well-known Multiphoton-BSS, Multiphoton-M-ary and Multiphoton-TSIV. Secondly, providing strong authentication is the main focus in this research which aims to make multiphoton QC secure against variety types of attacks. Current authentication procedure in multiphoton QC requires public agreement to pre-share the authentication key and secret angles before onset of the transmission, therefore increasing the communication cost. As a solution, a Secure Secret Authentication Key (SSAK) is proposed. In SSAK, the quantum handshake scheme is used to share initial secret polarization angle and authentication key which is utilized before quantum communication session. The results of simulation experiments reveal that SSAK significantly outperformed the Three-stage protocol in terms of average covered angle by Eve. The simulation experiments and security analysis of initial authentication and transmission of messages verified that an eavesdropper is unable to disclose any information about the transmitted message or the authentication key. Lastly, most of the proposed QKD protocol employs a single-beam set up to transmit the photons over the free space optic which results in low bit rate and limited distance coverage due to high impact of geometrical loss. To deal with this, a transmission technique of Multiphoton Quantum Communication using multiple beam concept (MQC-MB) is proposed. Comparison is conducted in terms of total loss and received power on different number of beam shows that 4-beam is acceptable to be adapted in MQC-MB. The statistical analysis shows that such approach has reduced the total attenuation by 6dB compared to single-beam setup.
This is a comparative study to explore the performance of three lossless compression techniques, namely Run Length Encoding (RLE), Shannon-Fano Coding (SFC), and Huffman Coding (HC) in the context of a Hybrid M-Ary in Braided Single Stage (HMBSS) protocol communication scheme. The previous study on HMBSS using HC found that HC's compression technique has drawbacks, i.e., it is sensitive to errors and noise in the transmission channel and limited to certain data types. These drawbacks did affect the value of the compression rate limit. In this study, we evaluate the effectiveness of RLE, SFC, and HC in terms of data size reduction, coding efficiency, and data transmission time by comparing their results arising from the simulation experiments using Python coding in Jupiter Notebook and developed based on the HMBSS protocol algorithm. This simulation experiment starts with an initial six randomly generated datasets. Each dataset is tested using three compression techniques, which resulted in 18 different datasets. The results from the experiments reveal that SFC and HC consistently achieved a higher compression ratio and coding efficiency than RLE. These two compression techniques' algorithms effectively reduce the data size while preserving the original information. In our study, we also find that the data transmission time is increased with larger text sizes for all three compression techniques. This indicates that the larger the data size, the more transmission time is required with regard to what the compression technique's algorithm is.
It was recently proposed to use quantum secure direct communication (QSDC), a branch of quantum cryptography, to secure data transfers from sender to receiver without relying on computational complexity. Despite the benefits of multiphoton, sending secret messages between several parties in a quantum channel still presents a challenge because the current multiphoton only considers two parties. When more parties are included, the scalability problem becomes apparent. Therefore, the scalable multiphoton approach is needed to allow secure sharing between the legal parties. The manipulation of level encoding provides new opportunities for more efficient quantum information processing and message sharing. This research aims to propose a strategy that uses four-level encoding with the multiphoton approach to share secret messages between multi-party. From the analysis conducted, it has been shown that a high number of level encoding can shorten the time taken for photon transmission between parties and an attacker has a lower probability of chances to launch an attack, however, communication will be affected due to high sensitivity to noise.
This is a comparative study to explore the performance of three lossless compression techniques, namely Run Length Encoding (RLE), Shannon-Fano Coding (SFC), and Huffman Coding (HC) in the context of a Hybrid M-Ary in Braided Single Stage (HMBSS) protocol communication scheme. The previous study on HMBSS using HC found that HC’s compression technique has drawbacks, i.e., it is sensitive to errors and noise in the transmission channel and limited to certain data types. These drawbacks did affect the value of the compression rate limit. In this study, we evaluate the effectiveness of RLE, SFC, and HC in terms of data size reduction, coding efficiency, and data transmission time by comparing their results arising from the simulation experiments using Python coding in Jupiter Notebook and developed based on the HMBSS protocol algorithm. This simulation experiment starts with an initial six randomly generated datasets. Each dataset is tested using three compression techniques, which resulted in 18 different datasets. The results from the experiments reveal that SFC and HC consistently achieved a higher compression ratio and coding efficiency than RLE. These two compression techniques’ algorithms effectively reduce the data size while preserving the original information. In our study, we also find that the data transmission time is increased with larger text sizes for all three compression techniques. This indicates that the larger the data size, the more transmission time is required with regard to what the compression technique’s algorithm is.
One of the objectives of information security is to maintain the confidentiality and integrity of the information by ensuring that information is transferred in a way that is secure from any listener or attacker. There was no comparison experiment conducted in earlier studies regarding different level encoding performance towards multiphoton technique. Multiphoton technique in the earlier study is particular to transmission time for data transfer encoding and extra time for polarizers to change polarisation angles, both of which contribute to longer transmission times. With four different size of qubits, the three simulation experiments are carried out using Python coding with 2,4 and 8 levels of encoding. Experiment results demonstrate that the most efficient average photon transmission derived from 18 qubit size ranges from 98.71% to 98.73% depending on encoding level. With 18 qubit size, the four-level encoding result has the highest average efficiency, followed by the eight-level and two-level encodings, respectively. 4-level encoding exhibits the highest average photon efficiency between 2 and 8 level encoding.
The security of Quantum Secure Direct Communication (QSDC) and its authentication procedure based on multiple stages is analyzed. The security analysis shows that the process of authentication is required to be done three times based on the usage of unitary transformation that is only known between Alice and Bob. In the proposed protocol, a secure quantum handshake is utilized to share the secret polarization angle and an authentication key at the initial stage of authentication over the quantum channel. The symmetry key is used in this work to protect user data communication within the QSDC protocol, where the same secret key is used to encrypt and decrypt the message. This work adopts the information travel time (ITT) by allowing the sender to detect any interference from third parties. In addition, the operation of the Pauli-X quantum gate increases Eve’s difficulty in stealing the information. The information transmitted is then continued by sending photons once in the quantum channel, which improves the efficiency without losing the message’s security. In addition, to securely transfer the stream of messages, the proposed protocol is operated in single-stage, and the authentication is applied bit-by-bit, thus reducing the transmission time. Security checks are carried out along the data transmission process. Compared to previous protocols, this new initial authentication protocol has remarkable advantages since it does not require public communication to pre-share the authentication key and secret angles before the onset of the transmission, therefore, reducing the communication cost. Moreover, the secret authentication key and polarization angles are updated after a number of bits are sent to increase the security level. The verification process is also conducted to ensure the symmetry of the sender and receiver. The analyses presented herein demonstrate that the proposed authentication protocol is simple and secure in order to ensure the legitimacy of the users.