Systematic Literature Review on Quantum Cryptography

In the field of cryptography, new tasks are generated when advancement has taken place from conventional computing to quantum computing. In case of computer security, cryptography had always been a valuable and essential tool.When quantum mechanics principles are applied to cryptography, it gives rise to a new system that will secure communication and also assures that no spying can take place.The work below presents the review on quantum cryptography, which includes the concept of quantum cryptography and what can be its evaluation measures. Articles of quantum cryptography from various databases has been studied. In this SLR various research questions are identified and on the basis of their answers results have been formulated for this review along with that various performance measures are also discussed.

Cryptography is the science dealing with the encryption and decryption of the data in order to secure it and avail a secure transmission. In order to do so, encryption is performed by adding additional information and the encrypted image (also known as CIPHER Image) is brought in the original form by performing decryption on it [17]. For the purpose keys are used which are randomly generated, but are vulnerable to eavesdropping but by employing Quantum communication, i.e. using key distribution accomplished by quantum cryptography, we can get rid of the problem. Thus Quantum Cryptography is actually a procedure of key distribution, but not the message itself.
Quantum Cryptography enforces better security as it is not possible to tap single signal. Hence, an eavesdropper can't intercept and retransmit the system because in quantum mechanics any observation can't be thought of as a possessed value. Also, Due to Heisenberg Uncertainty principle, any external activity would introduce an irreversible change in quantum states before they are transmitted to the receiver. Thus, resulting in a high error rate and intended receiver to detect the eavesdropping. Thus, quantum Cryptography on one hand ensures reliability of the key material, on the other hand detects any attempt of eavesdropping [18].
In 1984, Bennet and Bussarat published first quantum Cryptography protocol, known as BB84 [19]. In1991, Bennet et.al. [20] used polarized photons as a working prototype of BB84 protocol.In 1991, Ekerst [21] proposed the use of Einstein-Podol-Sky-Rosen entangled two state particles to implement a quantum cryptography protocol. In 1992, Bennet [21] proposed a quantum key distribution method, known as B92 could be implemented by employing 6 single photon interference with photon propagating for long distance over optical fiber. Afterwards, other protocols [22] were published and many groups [23] developed optical-fiber based prototype.

Differential measures
To crack the key, attackers often make a slight change in the plain image and then the slightly changed image is encrypted using the same secret key. Afterwards relationship between the encrypted original and modified image is looked upon, thus for better efficiency an algorithm must be sensitive towards the slightest change which is a test using NPCR (Number of pixel change rate) and UACI (Unified average changing intensity).
1.1. 1. NPCR: Number of pixel change rate is percentage of different pixel numbers between two encrypted images, whose original images have one pixel difference only. Higher value ensures higher reliability against differential attacks. It is given by: Where w and h denotes width and Height of the image respectively. D(i, j) denotes the difference between corresponding pixels of original encrypted image. Range of NPCR ϵ [0,100].

2.2.2
Correlation Coefficient (CC): It is a measure of similarity between corresponding pixels of an plain and encrypted image. The values of adjacent pixels of an original image are strongly correlated in three directions, i.e., horizontal, diagonal, and vertical. Reduction of this relationship in ciphered image ensures the capability of an algorithm agents statistical attacks. It is denoted by r and given by: Here, Where c(x, y) denotes the covariance between the samples x and y i.e. the coordinates of an image. Also D (x) and D (y) denotes the standard deviation of x and y, respectively. K is the number of pixel pairs (xi, yi) and ∑(x) is the mean of xi pixel values.

2.2.3
Peak Signal to Noise Ratio (PSNR): PSNR a quality measure between the original and decrypted images. PSNR is given by : Unit of measuring PSNR are decibel (dB). The value of PSNR for a better algorithm this value should be maximum.
In this article a different quantum cryptography techniques are reviewed by systematic way. This article helps to find various issues with systematically choosing the researching databases, selecting research papers and deciding their selection or refusal criteria. This study will help to the scholars as well as experts in selecting suitable quantum technique for cryptography. This systematic literature review is divided into following sections: v Methodology for literature review v Results v Conclusion and future scope

Methodology For Literature Review
The systematic literature study has been exploited to do this research. It is an appropriate and replication process to record significant points of awareness of the exact research range for reviewing and exploratory all current research recognized with research queries. Thus, this examination associates following phases like, identification of research queries, and selection and refusal conditions, and Data Search process.

Research Queries Identification
Research queries are formulated before starting the Systematic literature review and from the selected article's authors try to find the answers to research questions that are described in the Our next step is to design a procedure for searching the appropriate articles. For review procedures, we have deliberated search process, selection and refusal criteria, and data extraction.

Figure1. Article search
Figure1. Shows that we have chosen four valid databases (i.e. WOS, IEEE, PCM and Goggle scholar) with a specific procedure to complete our search. These prominent databases have maximum result regarding our query and we have selected the article via the self-designed process as described below.
We have year-wise selected range from "2015-2020" for selection of research articles for this Review from selected databases. We have applied AND operator in between keywords related to our topic for searching the articles. In this way the search process is refined and non-relevant articles are uninvolved.

Selection And Rejection Criteria
We describe the solid paradigm for the selecting and rejecting of the research articles for this SLR. Four parameters are considered to assure the correctness of the suitable responses to our research queries. The research articles will be selected on the principle of these factors as given below.
A. Selection i.
Year Wise Range 2015-2020 The Chosen research article must be dispersed from 2015 to 2020 by introducing the filter an off year-wise selection in each database that will result diminish overall results and supports in concluding the research article. All other articles are rejected that are not in the described range set in the year wise selection mechanism.
ii. Publisher Selected research articles must be published in one of the popular scientific databases that are selected, i.e. Goggle scholar, WOS, IEEE, and PCM. iii.

Crucial-Effects
Chosen research articles must have vital, valuable results with respect to image encryption under quantum cryptography. Terminate the research articles if its algorithm does not have a great contribution for image encryption. iv.

Results-Oriented
Selected research articles must be results-oriented, not a survey, review, or case study. Have a short look at the simulation result section of the selected studies and verify that its influence worth in the field of image encryption. Result confirmation must be carried out by a dominant survey if it does not so terminate that article.

B. REJECTION i. Repetition
All searches in an exact search setting can't be unified. Thus, terminate the research article if these are vague in the given search setting and just a single (published in journal) of them is chosen. ii.
Rejection on the Title Basis Selected research article can be acceptable by having a look at the title of the research paper. The title has been terminated if it is not matched with the SLR topics. iii.
Rejection on Abstract Basis.
Occasionally it is very hard to take judgment while selecting the research study by checking the title only of the article so in this respect it is essential to study the abstract of the research article from which we can get correct information about the research article.

Results Of The Systematic Review
The outcome of the review is addressed in the form of answers to the research questions.

Performance Measures
The generally used performance measures are correlation analysis, histogram, key sensitivity and key space. In any case, numerous presentation measures can be utilized depending on the kind of attacks.

Findings And Conclusions
The systematic literature review concludes that a significant amount of research was carried out in image encryption using quantum cryptography. The dispersion of research over the years is steady. The major image encryption approaches used are quantum walks, and NCQI Model. When the traditional algorithm of image encryption combined with quantum ideas it became very fast