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International Conference on Advanced Computing and Communication Systems (ICACCS)

Quantum Key Recovery Attack on Simplified Grain 4-Bit Cipher Using Grover's Algorithm

M. Mohankumar, Bhupendra Singh, T. Thamaraimanalan, Santosh Kumar Korada, P Yuvaraj, S Jyothikamalesh

Published Mar 14, 2024• 2 citations
Publisher

Abstract

In this paper, we proposed a simplified version of the Grain-128 stream cipher and developed a corresponding quantum circuit. Leveraging Grover's algorithm, we demonstrate the ability to recover a key given plaintext, initialization vector (IV), and corresponding ciphertext through various methods, including single pair, double pair series, and double pair parallel approaches. Using the Qiskit Quantum Development Kit (QDK), we conduct these attacks and estimate the required quantum resources. Our research reveals that the simplified grain cipher is vulnerable to quantum attacks, showing how quantum computing could affect cryptographic systems.

DOI
10.1109/icaccs60874.2024.10716920

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In this paper, we proposed a simplified version of the Grain-128 stream cipher and developed a corresponding quantum circuit. Leveraging Grover's algorithm, we demonstrate the ability to recover a key given plaintext, initialization vector (IV), and corresponding ciphertext through various methods, including single pair, double pair series, and double pair parallel approaches. Using the Qiskit Quantum Development Kit (QDK), we conduct these attacks and estimate the required quantum resources. Our research reveals that the simplified grain cipher is vulnerable to quantum attacks, showing how quantum computing could affect cryptographic systems.
“Grover's Algorithm: Quantum Search” explores Grover's Algorithm in the context of quantum search, beginning with an overview of its mechanics. The section includes a literature survey that covers Grover's algorithm, stream ciphers, and the Grover attack, as well as quantum resource estimation. The section then introduces a simplified 4-bit Grain cipher (with a 4-bit key and 4-bit IV), detailing its design, initialization, and key stream generation. Following this, the chapter discusses about key recovery using Grover's algorithm, with an emphasis on quantum circuit development for the simplified Grain 4-bit cipher. It outlines key steps in the circuit, such as executing the Boolean function and XORing the NFSR's fourth bit. Further, the section details the development of a Grover attack quantum circuit, describing both single and double pair methods. Experimental results are provided across multiple cases, with a summary of test cases and classical computation times. Quantum resource estimation, including the costs associated with the simplified Grain 4-bit cipher and the Grover oracle, is analyzed. The section concludes with a discussion on the results, classical and quantum resource estimations, and the potential for future enhancements to the approach.
Abstract A significant amount of study is being done to review the security promises made for the various ciphers now in use as a result of the development of quantum computing technology. A general attack against symmetric key cryptography primitives that can reduce search costs to the square root is Grover's search algorithm. To implement Grover's algorithm, it is necessary that the target cipher be implemented as a quantum circuit. Despite being relatively new, this area of study has received significant attention from the research community. The authors have estimated the cost of Grover's key search attack against the stream cipher Atom, for the first time, under circuit depth restrictions defined in National Institute of Standards and Technology (NIST) PQC standardisation process. The authors implement the quantum circuit of Atom in QISKIT, (open‐source software development kit for working with quantum computers running on IBM Quantum Experience). The results are also compared with other existing literature on LFSR‐based stream ciphers, such as Grain‐v1, Grain‐128‐AEAD, and Lizard. The authors also find that, to the best of their knowledge, in the existing literature on estimating the cost of Grover's attack on symmetric ciphers, Atom is the only 128‐bit key cipher that meets the threshold of ≈2 170 set by NIST for quantum security of 128‐bit key ciphers. The authors also analyse the security of Atom against quantum TMDTO attacks.
To evaluate the security of a symmetric cryptosystem against any quantum attack, the symmetric algorithm must be first implemented on a quantum platform. In this study, a quantum implementation of a classical block cipher is presented. A quantum circuit for a classical block cipher of a polynomial size of quantum gates is proposed. The entire work has been tested on a quantum mechanics simulator called libquantum. First, the functionality of the proposed quantum cipher is verified and the experimental results are compared with those of the original classical version. Then, quantum attacks are conducted by using Grover's algorithm to recover the secret key. The proposed quantum cipher is used as a black box for the quantum search. The quantum oracle is then queried over the produced ciphertext to mark the quantum state, which consists of plaintext and key qubits. The experimental results show that for a key of n-bit size and key space of N such that [Formula: see text], the key can be recovered in [Formula: see text] computational steps.
The security level of a cipher is a key parameter. While general-purpose quantum computers significantly threaten modern symmetric ciphers, other quantum approaches like quantum annealing have been less concerning. However, this paper argues that a quantum annealer specifically designed to attack Grain 128 and Grain 128a ciphers could soon be technologically feasible. Such an annealer would require 5,751 (6,761) qubits and 77,496 (94,865) couplers, with a qubit connectivity of 225 (245). This work also shows that modern stream ciphers like Grain 128 and Grain 128a may be vulnerable to quantum annealing attacks. Although the exact complexity of quantum annealing is unknown, heuristic estimates suggest that for many problems withNNNvariables, aN\sqrt{N}N​exponential advantage over simulated annealing may hold. We detail how to transform algebraic attacks on Grain ciphers into the QUBO problem, making our attack potentially more efficient than classical brute-force methods. We demonstrate that applying our attack to rescaled Grain cipher versions, Grainllland Grainlalala, overtakes brute-force and Grover’s attacks for sufficiently largelll, assuming quantum annealing’s exponential benefit over simulated annealing.
Abstract The advent of quantum computing necessitates a rigorous reassessment of classical cryptographic primitives, particularly lightweight block ciphers (LBCs) deployed in resource-constrained environments. This work presents a comprehensive quantum implementation and security analysis of the Feistel-based LBC MIBS against quantum cryptanalysis. Using the inherent reversibility of its structure, we develop a novel ancilla-free quantum circuit that optimizes qubit count and depth. For MIBS-64 and MIBS-80, our implementation achieves quantum costs of 23,371 and 24,363, requiring 128 and 144 qubits, respectively, with a depth of 4,768. We subsequently quantify the cipher’s vulnerability to Grover’s key-search algorithm under the NIST PQC security constraint M A X D E P T H MAXDEPTH\mathtt{M}\mathtt{A}\mathtt{X}\mathtt{D}\mathtt{E}\mathtt{P}\mathtt{T}\mathtt{H}MAXDEPTH . By constructing Grover oracles using inner parallelization with multiple plaintext-ciphertext pairs to suppress false positives, we demonstrate total quantum attack costs of approximately 2 94 for MIBS-64 and 2 111 for MIBS-80. These values fall below NIST’s Level-1 security threshold (2 170 ), confirming the susceptibility of both MIBS variants to quantum key-recovery attacks despite their classical lightweight efficiency.
Quantum computing plays a vital role in the next generation computing platforms as researchers have achieved quantum supremacy by proving that quantum computers can outperform classical computers. These high performance computers will pose a serious threat to the security of the conventional cryptographic algorithms. The secret key of the conventional cryptographic algorithms when implemented by quantum circuits can easily be recovered with the help of Grover key search algorithm. The Grover’s algorithm requires low cost quantum implementation of cryptographic algorithms in order to mount the quantum key recovery attack successfully. Hence the low cost quantum implementation of conventional cryptographic algorithms to mount quantum key recovery attack using Grover search algorithm is an active area of research. This work proposes a novel quantum circuit implementation of two lightweight block ciphers namely PUFFIN and PRINT and for the first time in literature In-place method is used to optimize the quantum resources in these two ciphers which helps to build compact quantum circuits without extra ancilla inputs. The performance metrics considered in this work to quantify the quantum resources of the proposed circuits are number of quantum gates, quantum cost, latency and number of qubits. In addition, the quantum resources are also estimated to mount the quantum key recovery attacks on the proposed quantum circuit implementations of PUFFIN and PRINT using Grover-based key search algorithm.