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Arpita Maitra

Publications and source records attributed to Arpita Maitra.

At least 19 recordsLinked to original sources

Provable DI-QRNG protocols based on self-testing methodologies in preparation and measure scenario

We present two Device Independent Quantum Random Number Generator (DI-QRNG) protocols using two self-testing methodologies in Preparation \& Measure (P\&M) scenario. These two methodologies are the variants of two well-known non-local games, namely, CHSH and pseudo-telepathy games, in P\&M framework. We exploit them as distinguishers in black-box settings to differentiate the classical and the quantum paradigms and hence to certify the Device Independence. The first self-test was proposed by Tavakoli et al. (Phys. Rev. A, 2018). We show that this is actually a P\&M variant of the CHSH game. Then based on this self-test, we design our first DI-QRNG protocol. We also propose a new self-testing methodology, which is the first of its kind that is reducible from pseudo-telepathy game in P\&M framework. Based on this new self-test, we design our second DI-QRNG protocol.

quant-ph↗

Experimental Simulation of Two Pulses and Three Pulses Coherent One Way Quantum Key Distribution Protocol in Noisy/Noiseless and Wired/Wireless Environment

Due to the rapid advancement of quantum technology, the traditional established classical cryptographic protocols are no longer secure. To make the world quantum safe, different quantum protocols have been taken into account. Quantum Key Distribution (QKD) protocols are one of them where two legitimate parties can securely communicate by upholding the quantum principles. Out of various QKD protocols, Coherent One Way (COW) protocol is one of the most famous protocol because of its ease of hardware deployment, and resilience nature towards PNS attack. In this initiative, we have implemented the original version of two pulses COW QKD protocol and a very recent variant of it, three pulses COW (Phys. Rev. Applied 18, 064053 Published 19 December 2022), in Optisystem v21.1. We demonstrate the encoding as well as decoding portions of the protocols under both noisy and noiseless scenario considering different weather conditions. Finally, we report a comparative study amongst the protocols under wired (optical fibre) and wireless (free space) environments to check the proper integrity of transmission. The simulation results provide us an overview regarding the practical implementation of the protocols under different weather conditions.

quant-ph↗

Improved and Formal Proposal for Device Independent Quantum Private Query

In this paper, we propose a novel Quantum Private Query (QPQ) scheme with full Device-Independent certification. To the best of our knowledge, this is the first time we provide such a full DI-QPQ scheme using EPR-pairs. Our proposed scheme exploits self-testing of shared EPR-pairs along with the self-testing of projective measurement operators in a setting where the client and the server do not trust each other. To certify full device independence, we exploit a strategy to self-test a particular class of POVM elements that are used in the protocol. Further, we provide formal security analysis and obtain an upper bound on the maximum cheating probabilities for both the dishonest client as well as the dishonest server.

quant-ph↗

Proposal for Quantum Ciphertext-Policy Attribute-Based Encryption

A Quantum Ciphertext-Policy Attribute-Based Encryption scheme (QCP-ABE) has been presented. In classical domain, most of the popular ABE schemes are based on the hardness of the Bilinear Diffie-Hellman Exponent problem, which has been proven to be vulnerable against Shor's algorithm. Recently, some quantum safe ABE schemes have been proposed exploiting the Lattice problem. However, no efficient Quantum Attribute-Based Encryption scheme has been reported till date. In this backdrop, in the present initiative, we propose a quantum CP-ABE scheme exploiting Quantum Key Distribution (QKD) and Quantum Error Correcting code. A Semi Quantum version of the scheme has also been considered. Finally, we introduced dynamic access structure in our proposed protocols.

quant-ph↗

Linear Cryptanalysis through the Lens of Clauser-Horne-Shimony-Holt Game

Application of CHSH game in Linear Cryptanalysis is presented. Till date, the known usage of CHSH game in Quantum Cryptology is to verify the device independence of the protocols. We observed that the classical symmetric ciphers having the bias equal to 0:25 can be improved to 0:35 exploiting the game which indicates clear improvement over existing Linear and Differential cryptanalysis. In the present initiative, we showed the application of the game in linear cryptanalysis on a lightweight cipher named SIMON. However, the approach can be extended to Differential cryptanalysis too. This observation opens a new direction of research in quantum cryptography.

quant-ph↗

Grover on SIMON

For any symmetric key cryptosystem with $n$-bit secret key, the key can be recovered in $O(2^{n/2})$ exploiting Grover search algorithm, resulting in the effective key length to be half. In this direction, subsequent work has been done on AES and some other block ciphers. On the other hand, lightweight ciphers like SIMON was left unexplored. In this backdrop, we present Grover's search algorithm on all the variants of SIMON and enumerate the quantum resources to implement such attack in terms of NOT, CNOT and Toffoli gates. We also provide the T-depth of the circuits and the number of qubits required for the attack. We show that the number of qubits required for implementing Grover on SIMON $2n/mn$ is $O(2nr+mn)$, where $r$ is the number of chosen plaintext-cipher text pairs. We run a reduced version of SIMON in IBMQ quantum simulator and the 14-qubits processor as well. We found that where simulation supports theory, the actual implementation is far from the reality due to the infidelity of the gates and short decoherence time of the qubits. The complete codes for all version of SIMON have also been presented.

quant-ph↗

Generalized Theoretical Approach for Analysing Optical Experiments

A generalized approach towards modelling any optical experiment is presented. Beam splitter and phase retarders are described in terms of annihilation and creation operators. We notice that such description provides us a better way to analyze any optical experiment mathematically than Jones matrix algebra. We represent polarization of photon in Fock state basis. We consider recently demonstrated wave-particle superposition generation experiment (Nature Communication, 2017) and Passive BB84 with coherent light (Progress in Informatics, 2011) to test our methodology. We observe that our disciplined methodology can successfully describe the experiments with greater ease, hence offering a convenient tool for modelling any optical arrangement.

quant-ph↗

Dimensionality Distinguishers

The celebrated Clauser, Horne, Shimony and Holt (CHSH) game model helps to perform the security analysis of many two-player quantum protocols. This game specifies two Boolean functions whose outputs have to be computed to determine success or failure. It also specifies the measurement bases used by each player. In this paper, we generalize the CHSH game by considering all possible non-constant Boolean functions and all possible measurement basis (up to certain precision). Based on the success probability computation, we construct several equivalence classes and show how they can be used to generate three classes of dimension distinguishers. In particular, we demonstrate how to distinguish between dimensions 2 and 3 for a special form of maximally entangled state.

quant-ph↗

Likelihood Theory in a Quantum World: tests with Quantum coins and computers

By repeated trials, one can determine the fairness of a classical coin with a confidence which grows with the number of trials. A quantum coin can be in a superposition of heads and tails and its state is most generally a density matrix. Given a string of qubits representing a series of trials, one can measure them individually and determine the state with a certain confidence. We show that there is an improved strategy which measures the qubits after entangling them, which leads to a greater confidence. This strategy is demonstrated on the simulation facility of IBM quantum computers.

quant-ph↗

Proposal for Dimensionality Testing in Quantum Private Query

Recently, dimensionality testing of a quantum state has received extensive attention (Ac{í}n et al. Phys. Rev. Letts. 2006, Scarani et al. Phys. Rev. Letts. 2006). Security proofs of existing quantum information processing protocols rely on the assumption about the dimension of quantum states in which logical bits are encoded. However, removing such assumption may cause security loophole. In the present paper, we show that this is indeed the case. We choose two players' quantum private query protocol by Yang et al. (Quant. Inf. Process. 2014) as an example and show how one player can gain an unfair advantage by changing the dimension of subsystem of a shared quantum system. To resist such attack we propose dimensionality testing in a different way. Our proposal is based on CHSH like game. As we exploit CHSH like game, it can be used to test if the states are product states for which the protocol becomes completely vulnerable.

quant-ph↗

Measurement Device Independent Quantum Private Query with Qutrits

Measurement Device Independent Quantum Private Query (MDI QPQ) with qutrits is presented. We compare the database security and client's privacy in MDI QPQ for qubits with qutrits. For some instances, we observe that qutrit will provide better security for database than qubit. However, when it comes to the question of client's privacy we have to take additional measures in case of qutrit. Hence we conclude that though in case of Quantum Key Distribution (QKD) higher dimension provides better security but in case of QPQ this is not obvious.

quant-ph↗

Quantum secure two party computation for set intersection with rational players

Recently, Shi et al. (Phys. Rev. A, 2015) proposed Quantum Oblivious Set Member Decision Protocol (QOSMDP) where two legitimate parties, namely Alice and Bob, play a game. Alice has a secret $k$ and Bob has a set $\{k_1,k_2,\cdots k_n\}$. The game is designed towards testing if the secret $k$ is a member of the set possessed by Bob without revealing the identity of $k$. The output of the game will be either "Yes" (bit $1$) or "No" (bit $0$) and is generated at Bob's place. Bob does not know the identity of $k$ and Alice does not know any element of the set. In a subsequent work (Quant. Inf. Process., 2016), the authors proposed a quantum scheme for Private Set Intersection (PSI) where the client (Alice) gets the intersected elements with the help of a server (Bob) and the server knows nothing. In the present draft, we extended the game to compute the intersection of two computationally indistinguishable sets $X$ and $Y$ possessed by Alice and Bob respectively. We consider Alice and Bob as rational players, i.e., they are neither "good" nor "bad". They participate in the game towards maximizing their utilities. We prove that in this rational setting, the strategy profile $((cooperate, abort), (cooperate, abort)$) is a strict Nash equilibrium. If $((cooperate, abort), (cooperate, abort)$) is strict Nash, then fairness as well as correctness of the protocol are guaranteed.

quant-ph↗

Measurement Device Independent Quantum Dialogue

Very recently, the experimental demonstration of Quantum Secure Direct Communication (QSDC) with state-of-the-art atomic quantum memory has been reported (Phys. Rev. Lett., 2017). Quantum Dialogue (QD) falls under QSDC where the secrete messages are communicated simultaneously between two legitimate parties. The successful experimental demonstration of QSDC opens up the possibilities for practical implementation of QD protocols. Thus, it is necessary to analyze the practical security issues of QD protocols for future implementation. Since the very first proposal for QD by Nguyen (Phys. Lett. A, 2004) a large number of variants and extensions have been presented till date. However, all of those leak half of the secret bits to the adversary through classical communications of the measurement results. In this direction, motivated by the idea of Lo et al. (Phys. Rev. Lett., 2012), we propose a Measurement Device Independent Quantum Dialogue (MDI-QD) scheme which is resistant to such information leakage as well as side channel attacks. In the proposed protocol, Alice and Bob, two legitimate parties, are allowed to prepare the states only. The states are measured by an untrusted third party (UTP) who may himself behave as an adversary. We show that our protocol is secure under this adversarial model. The current protocol does not require any quantum memory and thus it is inherently robust against memory attacks. Such robustness might not be guaranteed in the QSDC protocol with quantum memory (Phys. Rev. Lett., 2017).

quant-ph↗

Device Independent Quantum Private Query with Finite Number of Entangled Qubits

In a recent work by Maitra et al. (Phys. Rev. A, 2017), it was shown that the existing Quantum Private Query (QPQ) protocols fail to maintain the database security if the entangled states shared between Alice and Bob are not of a certain form. So it is necessary to certify the states a priori. In this regard, the local CHSH test was proposed. However, the proposed scheme works perfectly for the asymptotic case when we have infinite number of qubits. In this brief report, we upgrade the protocol for finite number of qubits and connect the sample size to the success probability of CHSH test. We also perform a rigorous security analysis of the proposed protocol.

quant-ph↗

Device Independent Quantum Private Query

In Quantum Private Query (QPQ), a client obtains values corresponding to his query only and nothing else from the server and the server does not get any information about the queries. Giovannetti et al. (Phys. Rev. Lett., 2008) gave the first QPQ protocol and since then quite a few variants and extensions have been proposed. However, none of the existing protocols are device independent, i.e., all of them assume implicitly that the entangled states supplied to the client and the server are as prescribed. In this work, we exploit the idea of local CHSH game and connect it with the scheme of Yang et al. (Quantum Inf. Process., 2014) to present the concept of device independent QPQ protocol for the first time.

quant-ph↗

Secure two-party quantum computation for non-rational and rational settings

Since the negative result of Lo (Physical Review A, 1997), it has been left open whether there exist some functions that can be securely computed in two-party setting in quantum domain when one of the parties is malicious. In this paper, we for the first time, show that there are some functions for which secure two-party quantum computation is indeed possible for non-simultaneous channel model. This is in sharp contrast with the impossibility result of Ben -Or et al. (FOCS, 2006) in broadcast channel model. The functions we study are of two types - one is any function without an embedded XOR, and the other one is a particular function containing an embedded XOR. Contrary to classical solutions, security against adversaries with unbounded power of computation is achieved by the quantum protocols due to entanglement. Further, in the context of secure multi-party quantum computation, for the first time we introduce rational parties, each of whom tries to maximize its utility by obtaining the function output alone. We adapt our quantum protocols for both the above types of functions in rational setting to achieve fairness and strict Nash equilibrium.

cs.CR↗

Proposal for Quantum Rational Secret Sharing

A rational secret sharing scheme is a game in which each party responsible for reconstructing a secret tries to maximize his utility by obtaining the secret alone. Quantum secret sharing schemes, either derived from quantum teleportation or from quantum error correcting code, do not succeed when we assume rational participants. This is because all existing quantum secret sharing schemes consider that the secret is reconstructed by a party chosen by the dealer. In this paper, for the first time, we propose a quantum secret sharing scheme which is resistant to rational parties. The proposed scheme is fair (everyone gets the secret), correct and achieves strict Nash equilibrium.

quant-ph↗

A Resilient Quantum Secret Sharing Scheme

A resilient secret sharing scheme is supposed to generate the secret correctly even after some shares are damaged. In this paper, we show how quantum error correcting codes can be exploited to design a resilient quantum secret sharing scheme, where a quantum state is shared among more than one parties.

quant-ph↗