Browsing by Author "Mohit Joshi"

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Impact of hardware connectivity on Grover’s algorithm in NISQ era
(Springer, 2025) Mohit Joshi; Manoj Kumar Mishra; S. Karthikeyan
The quantum search operation as dictated in Grover’s landmark paper had been a crucial area in the study of quantum algorithms. It has become a critical component in many quantum cryptography and computation algorithms and threatens today’s AES security infrastructure. The quadratic speedup provided by Grover’s algorithm is hampered severely due to the presence of a realistic environment. Many studies have analyzed the effect of different noises on Grover’s search algorithm. However, the efficiency of the algorithm also depends on the connectivity of qubits on realistic quantum hardware. This study evaluated the performance of Grover’s algorithm with varying qubit connectivity under the presence of two-qubit depolarizing noise and single-qubit amplitude damping and dephasing noise. Unidirectional and bidirectional variants of nine coupling maps for qubit connectivity were chosen. The analysis has shown that the transpilation efficiency for Grover’s algorithm is deeply sensitive to the connectivity and degree of the hardware, which influences the depth of the circuit. This, in turn, has a measurable effect on the performance of the algorithm on a particular hardware. This study also ranks the favorable coupling maps using the decision-making technique of AHP-TOPSIS. The analysis has shown that grid, hex, and modified star are the most favorable hardware connectivity. The unidirectional linear, ring, star, and full-connected are the worst choices. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.
Leveraging Grover’s Algorithm for Quantum Searchable Encryption in Cloud Infrastructure and its application in AES Resource Estimation
(Springer, 2024) Mohit Joshi; Manoj Kumar Mishra; S. Karthikeyan
Designing efficient techniques to search over encrypted data space has always been an intriguing security challenge, although many solutions based on classical searching methods have been proposed. Grover’s algorithm, a quantum counterpart of searching algorithms, has proven to provide quadratic speedup over any classical search technique on an unsorted database. However, this algorithm is unable to search over encrypted data space. This study proposed an extension of Grover’s algorithm to enable search over encrypted dataspace, allowing clients with limited-capability quantum resources to delegate complex search operations to an untrusted server. The blindness of data in this protocol is achieved by encrypting qubits using Pauli’s rotation gates that maximally mix the outgoing states. The empirical estimation of the overhead of the computation due to the introduction of this technique has been analyzed. This estimate has been used for comparative analysis, showing the efficiency of the proposed protocol. A practical application of the proposed searchable encryption technique has been utilized to estimate the increase in resources needed to carry out a brute-force attack on AES encryption using secure Grover’s algorithm. Furthermore, an extensive experimental analysis of the effect of noise has been studied using four different noise models: amplitude damping, phase damping, depolarizing noise, and bit-flip noise. The investigation provided useful insight into the behavior of the proposed algorithm under noisy conditions and also estimated the tolerance thresholds of the proposed algorithm under different noise models. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.
Quantum computing and new dimensions in network security
(CRC Press, 2024) Mohit Joshi; Alka; Manoj Kumar Mishra
Quantum computing is an emerging field of interest for many branches of practical computation ranging from cryptography to machine learning, from molecule design to drug discovery, and from physical simulations to financial optimization. Recent years have seen tremendous growth in the hardware and software applicability of quantum technology. It has started showing both disruptive and constructive implications for modern cryptography. New techniques of network security are now emerging that have no counterparts in classical cryptography. This chapter explores the horizons of network security using quantum computation. The chapter first introduces the general audience to quantum computation from the perspective of a computer scientist. It elaborates on the basic principles of quantum computing and helps to set up an intuitive understanding of this new paradigm of computation. The chapter also gives a brief introduction to the circuit model of quantum programming, which is the most prevalent model of quantum programming. It establishes the need for and importance of quantum cryptography and discusses various protocols of quantum security. © 2025 selection and editorial matter, Suhel Ahmad Khan, Mohammad Faisal, Nawaf Alharbe, Rajeev Kumar and Raees Ahmad Khan. All rights reserved.
Recent Trends and Open Challenges in Blind Quantum Computation
(Springer Science and Business Media Deutschland GmbH, 2023) Mohit Joshi; S. Karthikeyan; Manoj Kumar Mishra
Quantum mechanics with radically novel properties: such as superposition, entanglement, and the no-cloning theorem, has begun to open up Quantum Computation beyond the scope of Classical Computation. In recent years, quantum technology has seen tremendous leaps both in academic research and commercial exploration. Quantum computation has started to find applications in many more new domains every day, from disrupting modern cryptography to enabling unconventional security techniques, from quantum chemistry to physical simulations, and from quantum machine learning to financial optimization. This paper first provides the conceptual groundings of quantum computation and explores blind quantum computation, a one-of-its-kind sub-categorization of quantum computing active research. The use of Blind Quantum Computation in Quantum Cryptography is elaborated in detail. Finally concludes with highlights of the applicability of the subject. The paper is an easy-to-follow guide introducing the research trends and open challenges for the new researcher in follow-up on the field. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.