The security of efficient post-quantum cryptographic primitives, particularly those based on the Ring Learning With Errors (Ring-LWE) problem, relies fundamentally on the presumed intractability of the Shortest Vector Problem (SVP) over ideal lattices. This monograph investigates the hardness of Ideal-SVP in the presence of quantum adversaries. We rigorously analyze the worst-case to average-case reductions that underpin the security of ideal lattice-based schemes, extending classical Gaussian smoothing arguments to the quantum setting. Specifically, we examine the impact of quantum sieving algorithms and the Quantum Fourier Transform (QFT) on the algebraic structure of number fields. While quantum algorithms provide a quadratic speedup for general lattice sieving, we argue that the additional algebraic structure of ideal lattices does not yield a catastrophic collapse in hardness under current quantum reduction models. We present a synthesis of recent results concerning the lower bounds of quantum query complexity for Ideal-SVP, establishing that for cyclotomic fields of degree n, the problem remains hard up to sub-exponential factors, thereby validating the asymptotic security of structured lattice cryptography.
The security of efficient post-quantum cryptographic primitives, particularly those based on the Ring Learning With Errors (Ring-LWE) problem, relies fundamentally on the presumed intractability of the Shortest Vector Problem (SVP) over ideal lattices. This monograph investigates the hardness of Ideal-SVP in the presence of quantum adversaries. We rigorously analyze the worst-case to average-case reductions that underpin the security of ideal lattice-based schemes, extending classical Gaussian smoothing arguments to the quantum setting. Specifically, we examine the impact of quantum sieving algorithms and the Quantum Fourier Transform (QFT) on the algebraic structure of number fields. While quantum algorithms provide a quadratic speedup for general lattice sieving, we argue that the additional algebraic structure of ideal lattices does not yield a catastrophic collapse in hardness under current quantum reduction models. We present a synthesis of recent results concerning the lower bounds of quantum query complexity for Ideal-SVP, establishing that for cyclotomic fields of degree n, the problem remains hard up to sub-exponential factors, thereby validating the asymptotic security of structured lattice cryptography.
The security of cryptographic protocols is based on the presumed difficulty of algorithmic problems. Among those identified so far, some of the best problems to serve as a foundation for quantum-proof cryptography come from lattices. Lattices are a mathematical structure defined as a set of space vectors generated by integer combinations of a finite number of linearly independent real vectors (its basis). A typical example of a related security problem is the Shortest Vector Problem (SVP). Given a base of an n-dimensional lattice, find a non-zero short vector. For efficiency reasons, these problems are restricted to lattices arising from number theory, known as structured lattices. As the security assumptions for these particular lattices are different from those for unstructured lattices, it is necessary to study them specifically, which is the aim of this thesis.We have studied the case of NTRU and uSVP modules in rank 2, proving that the SVP problem is equivalent on these two families of lattices. We also show a worst-case to average-case reduction for rank-2 uSVP lattices. Then we show that solving SVP on a prime ideal of small norm is no easier than solving SVP on any ideal.
The imminent threat of quantum computing poses a significant challenge to the security of current public-key cryptographic systems, most notably RSA. These classical algorithms rely on mathematical problems, such as integer factorization and discrete logarithms, which are efficiently solvable by Shor's algorithm on a sufficiently powerful quantum computer. This paper explores ideal lattices as a robust post-quantum foundation for asymmetric cryptography, offering a compelling alternative to traditional schemes. We delve into the mathematical underpinnings of ideal lattices, including the Ring Learning With Errors (RLWE) and Shortest Vector Problem (SVP), which are conjectured to be hard even for quantum computers. The advantages of ideal lattice-based cryptography, such as its quantum resistance, efficiency, and versatility in constructing various cryptographic primitives, are thoroughly discussed. We examine prominent examples like NTRU and CRYSTALS-Kyber, highlighting their design principles and performance characteristics. Furthermore, the paper addresses the ongoing standardization efforts by NIST and the practical considerations for migrating to lattice-based schemes. The objective is to present a comprehensive analysis demonstrating why ideal lattices are a leading candidate for securing digital communications in the quantum era, providing a secure and efficient pathway beyond the limitations of RSA.
The advent of quantum computing poses a significant existential threat to the security of contemporary public-key cryptographic systems, such as RSA and Elliptic Curve Cryptography (ECC), which underpin global digital communication and secure transactions. These systems rely on the computational hardness of problems like integer factorization and the discrete logarithm problem, which are efficiently solvable by Shor's algorithm on a sufficiently powerful quantum computer. This paper comprehensively rethinks the foundations of public-key cryptography by exploring ideal lattice-based schemes as a promising, quantum-secure alternative. We delve into the mathematical underpinnings of ideal lattices, particularly focusing on their compact representation and efficient arithmetic derived from polynomial rings. We elucidate how the conjectured hardness of ideal lattice problems, such as the Ring Learning With Errors (RLWE) problem and the Ideal Shortest Vector Problem (Ideal-SVP), provides robust security against both classical and quantum adversaries. Through a detailed analysis of their cryptographic properties, efficiency benefits, and security guarantees, we argue for the critical role of ideal lattices in forging the next generation of resilient public-key infrastructures. This research highlights the advantages of ideal lattices in terms of performance and security compactness, making them leading candidates in the ongoing standardization efforts for post-quantum cryptography.
The advent of quantum computing poses a significant existential threat to current public-key cryptographic systems, most notably RSA and Elliptic Curve Cryptography (ECC), which rely on the presumed hardness of integer factorization and discrete logarithm problems. Shor's algorithm, a quantum algorithm, can efficiently solve these problems, rendering classical asymmetric primitives insecure. This paper addresses the imperative need for post-quantum cryptography (PQC) by exploring lattice-based constructs as robust alternatives for asymmetric primitives. We provide a comprehensive overview of the fundamental mathematical problems underlying lattice-based cryptography, such as the Shortest Vector Problem (SVP), Closest Vector Problem (CVP), Learning With Errors (LWE), and Ring Learning With Errors (RLWE). The paper surveys prominent lattice-based schemes, including NTRU, CRYSTALS-Kyber, and CRYSTALS-Dilithium, analyzing their security foundations, performance characteristics, and the extent to which they offer a viable "post-quantum RSA." We delve into the methodology of constructing these primitives, discuss their resilience against both classical and quantum attacks, and evaluate their practical implications for key sizes, computational efficiency, and deployment challenges. Our analysis highlights that lattice-based cryptography, particularly the NIST-standardized schemes, presents a strong candidate for securing digital communications in the quantum era, offering provable security rooted in worst-case to average-case reductions for lattice problems.
Abstract. Lattice-based cryptography is one of the candidates in the area of post-quantum cryptography. Cryptographic schemes with security reductions to hard lattice problems (like the Shortest Vector Problem SVP) offer an alternative to recent number theory-based schemes. In order to guarantee asymptotic efficiency, most lattice-based schemes are instantiated using polynomial rings over integers. These lattices are called ideal lattices. It is assumed that the hardness of lattice problems in lattices over integer rings remains the same as in regular lattices. In order to prove or disprove this assumption, we instantiate random ideal lattices that allow to test algorithms that solve SVP and its approximate version. The Ideal Lattice Challenge allows online submission of short vectors to enter a hall of fame for full comparison. We adjoin a set of first experiments and a first comparison of ideal and regular lattices.
The advent of quantum computing poses a significant threat to the security of current asymmetric cryptographic systems, which underpin much of modern digital communication and security. These systems, predominantly RSA and Elliptic Curve Cryptography (ECC), rely on the computational hardness of mathematical problems such as integer factorization and the discrete logarithm problem. Shor's algorithm, a quantum algorithm, demonstrates the ability to efficiently solve these problems, rendering classical public-key cryptography vulnerable to attacks by sufficiently powerful quantum computers. This paper argues for and thoroughly examines the strategic imperative of transitioning from these classical cryptographic foundations to a new paradigm based on lattices, which are believed to be resistant to quantum attacks. We delve into the fundamental mathematical problems underlying lattice-based cryptography, such as the Shortest Vector Problem (SVP) and the Learning With Errors (LWE) problem, whose worst-case hardness is leveraged to achieve cryptographic security. A comprehensive literature review is provided, tracing the evolution of quantum threats and the emergence of lattice-based schemes. The methodology details the construction principles of prominent lattice-based cryptosystems. Results demonstrate their theoretical security against quantum adversaries and highlight their practical attributes, including compact key sizes and competitive performance. The discussion section contextualizes lattice-based cryptography within the broader landscape of post-quantum candidates, examining their strengths, weaknesses, and the ongoing standardization efforts by organizations like NIST. We conclude that lattice-based cryptography offers a robust and promising foundation for building resilient asymmetric cryptographic systems in the post-quantum era, ensuring the long-term security of digital information through a necessary re-architecture of cryptographic primitives.