The advent of quantum computers poses a significant threat to the security of classical cryptographic systems. To address this concern, researchers have been actively investigating the development of post-quantum cryptography, which aims to provide encryption schemes that remain secure even in the face of powerful quantum adversaries. To address this serious problem, the National Institute of Standards and Technology (NIST), a body of the US government, has been working on the selection and standardization of cryptographic algorithms through competitive and rigorous evaluation on different fronts. NIST has selected different candidate algorithms to standardize public-key encryption, including key establishment algorithms and digital signature algorithms. This paper reviews some selected cryptosystems, mainly based on lattice- and code-based cryptosystems. These include digital signature algorithms, such as CRYSTALS-Dilithium, code-based cryptosystems, such as McEliece, and key encapsulation methods, specifically, Classic McEliece, BIKE and HQC. We will review these algorithms and discuss their security aspects and the current state-of-the-art in the development of these algorithms post NIST 3rd finalized selection. We will also touch briefly on the differences and practical applications of each of these schema. This review is intended for engineers and practitioners alike.
The advent of quantum computers poses a significant threat to the security of classical cryptographic systems. To address this concern, researchers have been actively investigating the development of post-quantum cryptography, which aims to provide encryption schemes that remain secure even in the face of powerful quantum adversaries. To address this serious problem, the National Institute of Standards and Technology (NIST), a body of the US government, has been working on the selection and standardization of cryptographic algorithms through competitive and rigorous evaluation on different fronts. NIST has selected different candidate algorithms to standardize public-key encryption, including key establishment algorithms and digital signature algorithms. This paper reviews some selected cryptosystems, mainly based on lattice- and code-based cryptosystems. These include digital signature algorithms, such as CRYSTALS-Dilithium, code-based cryptosystems, such as McEliece, and key encapsulation methods, specifically, Classic McEliece, BIKE and HQC. We will review these algorithms and discuss their security aspects and the current state-of-the-art in the development of these algorithms post NIST 3rd finalized selection. We will also touch briefly on the differences and practical applications of each of these schema. This review is intended for engineers and practitioners alike.
The emergence of quantum computing is a serious threat to the principles of modern crypto-logical mathematics. The classical public-key cryptography, including Rivest-Shamir-Adleman (RSA), Elliptic Curve Cryptography (ECC), and Diffie-Hellman are very safe against classical adversaries yet become susceptible to quantum algorithms, including the Shor algorithm, which can easily solve the underlying mathematical problems. This weakness is jeopardizing confidentiality and integrity of the world-wide systems of communication, money transactions, and essential structures, and requires the immediate creation of safe alternatives. The current literature on post-quantum cryptography (PQC) has covered various classes of algorithm, such as lattice-based, code-based, multivariate schemes, and isogeny-based schemes. Although lattice-based approaches like Nth Degree Truncated Polynomial Ring Unit (NTRU) and FrodoKEM can be highly theoretically resistant, they can be computationally and memory-intensive. Cryptosystems based on code such as Classic McEliece are secure but not practicable because they have huge public key sizes. Multivariate schemes like Rainbow, and isogeny-based schemes like Super singular Isogeny Key Encapsulation (SIKE) have been attacked recently by cryptanalytic attacks, and broken completely. Such restrictions open the necessity to find more efficient and secure quantum-resistant solutions.This research study postulates a hybrid post-quantum cryptographic (PQC) system that combines CRYSTALS-Kyber for encryption with CRYSTALS-Dilithium for digital signatures both of which are approved through the National Institute of Standards and Technology (NIST) PQC standardization program. The model will be such that it ensures quantum resistance but at the same time it will be scalable, efficient and compatible with the existing infrastructures. The test outcomes indicate that the hybrid PQC model is 35-45 percent faster to encrypt and decrypt, signature performance is enhanced by up to 40 percent, and the throughput is 20 times higher (98.7 Mbps) than the same base PQC scheme including Nth Degree Truncated Polynomial Ring Unit (NTRU), McEliece and Rainbow. These enhancements affirm that the suggested model provides a viable trade-off between the security, speed, and efficiency in terms of key size, which makes it a viable and a sound base to ensure secure communication in the quantum age.
The advent of quantum computing poses a significant threat to current cryptographic systems, particularly public-key algorithms such as RSA and ECC, which are vulnerable to quantum attacks like Shor's algorithm. Post-Quantum Cryptography (PQC) aims to develop and standardize quantum-resistant cryptographic algorithms to secure digital communications in the quantum era. This paper examines the current landscape of PQC, focusing on the evaluation and standardization efforts led by organizations such as the National Institute of Standards and Technology (NIST). We analyze the major families of quantum-resistant algorithms, including lattice-based, hash-based, code-based, multivariate, and isogeny-based cryptography, discussing their security guarantees, performance trade-offs, and implementation challenges. Furthermore, we review NIST's PQC standardization process, highlighting selected finalists and alternate candidates, and explore the ongoing transition challenges in adopting these algorithms across industries. Finally, we discuss future directions for PQC research, including hybrid cryptographic systems and the need for continued cryptanalysis to ensure long-term security. This work provides a comprehensive overview of the progress and challenges in deploying quantum-resistant cryptography to safeguard against emerging quantum threats.
Information security is a fundamental and urgent issue in the digital transformation era. Cryptographic techniques and digital signatures have been applied to protect and authenticate relevant information. However, with the advent of quantum computers and quantum algorithms, classical cryptographic techniques have been in danger of collapsing because quantum computers can solve complex problems in polynomial time. Stemming from that risk, researchers worldwide have stepped up research on post-quantum algorithms to resist attack by quantum computers. In this review paper, we survey studies in recent years on post-quantum cryptography (PQC) and provide statistics on the number and content of publications, including a literature overview, detailed explanations of the most common methods so far, current implementation status, implementation comparisons, and discussion on future work. These studies focused on essential public cryptography techniques and digital signature schemes, and the US National Institute of Standards and Technology (NIST) launched a competition to select the best candidate for the expected standard. Recent studies have practically implemented the public key encryption/key encapsulation mechanism (PKE/KEM) and digital signature schemes on different hardware platforms and applied various optimization measures based on other criteria. Along with the increasing number of scientific publications, the recent trend of PQC research is increasingly evident and is the general trend in the cryptography industry. The movement opens up a promising avenue for researchers in public key cryptography and digital signatures, especially on algorithms selected by NIST.
The security of most widely used public-key cryptography is fundamentally based on two computationally intractable problems: the integer factorization problem and the elliptic-curve discrete logarithm problem. However, these problems can be solved easily in polynomial time with the help of large-scale quantum computers using Shor's, Proos and Zalka's algorithm. Post-quantum cryptography provides schemes based on hard problems that are hard-to-solve not only by adversaries with classical computers but also by adversaries with large-scale quantum computers. Lattice-based cryptography is a branch of post-quantum cryptography consisting of schemes based on hard lattice problems. The National Institute of Standards and Technology (NIST) recently published the first set of standard post-quantum schemes. Kyber and HQC are the standard key-encapsulation mechanism/public-key encryption schemes, whereas Dilithium, Sphincs+, and Falcon are the standard digital signature algorithms. Although NIST's selection of the first set of post-quantum cryptographic standards is one of the most significant steps toward the transition from classical public-key cryptography to post-quantum cryptography, the field of post-quantum cryptography is still in a nascent stage compared to the decade-old classical public-key cryptography, such as RSA or ECDSA. Therefore, a major focus of this thesis is to bridge the gap between the theory and practice of post-quantum cryptography by exploring various problems that arise during the real-world deployment of post-quantum cryptography. Specifically, I focus on improving the practicality of lattice-based cryptography by proposing new efficient schemes, designing lightweight post-quantum schemes suitable for resource-constrained devices, efficient implementations, analyzing practical physical attacks on implementations of the post-quantum schemes, and designing their countermeasures to thwart the attacks. The first area of research of this dissertation is the exploration of various design choices for lattice-based key-encapsulation mechanisms to make them suitable in different environments under various operational constraints such as memory, silicon area, execution time, power requirement, etc. In our first contribution, we have explored various design choices for lattice-based key-encapsulation mechanisms, focusing on improving execution time on various hardware and software platforms. Our first design, Scabbard, is a suite of three key-encapsulation mechanisms that improved the state-of-the-art post-quantum key-encapsulation mechanism designs by reducing execution time, stack memory requirements, and/or area footprint. In our second contribution, we performed another design space exploration based on hardware resources (such as block RAM, distributed RAM, look-up tables, etc.) estimation and proposed the lattice-based key-encapsulation mechanism, Rudraksh, for resource-constrained devices. We also substantiate our claim of its usefulness with real-world implementations on an FPGA. The second area of research of this dissertation is the analysis of physical attacks. This attack analysis is essential when the attacker can access a device that executes cryptographic implementations, and such scenarios occur frequently in real-world deployments. Therefore, this is a crucial problem to address before deploying post-quantum cryptographic schemes in real-world applications, and countermeasures against physical attacks need to be developed as a prevention measure. In our third contribution, we proposed side-channel attack-resistant masked implementations of lattice-based KEM, Saber KEM, one of the NIST finalist KEMs. We showed that masked Saber outperforms the state-of-the-art masked implementations of Kyber, one of the NIST standards. Our investigations show that this is largely due to power-of-two moduli. Our final contribution to this thesis is physical attack analyses on implementations of the standard key-encapsulation mechanism Kyber. We proposed a cross-attack, fault-injection attack on the masked implementation of Kyber. We showed that the exploited vulnerability was introduced due to the algorithmic change caused by masking.
Recent developments in quantum computing have shed light on the shortcomings of the conventional public cryptosystem. Even while Shor's algorithm cannot yet be implemented on quantum computers, it indicates that asymmetric key encryption will not be practicable or secure in the near future. The National Institute of Standards and Technology (NIST) has started looking for a post-quantum encryption algorithm that is resistant to the development of future quantum computers as a response to this security concern. The current focus is on standardizing asymmetric cryptography that should be impenetrable by a quantum computer. This has become increasingly important in recent years. Currently, the process of standardizing asymmetric cryptography is coming very close to being finished. This study evaluated the performance of two post-quantum cryptography (PQC) algorithms, both of which were selected as NIST fourth-round finalists. The research assessed the key generation, encapsulation, and decapsulation operations, providing insights into their efficiency and suitability for real-world applications. Further research and standardization efforts are required to enable secure and efficient post-quantum encryption. When selecting appropriate post-quantum encryption algorithms for specific applications, factors such as security levels, performance requirements, key sizes, and platform compatibility should be taken into account. This paper provides helpful insight for post-quantum cryptography researchers and practitioners, assisting in the decision-making process for selecting appropriate algorithms to protect confidential data in the age of quantum computing.
In recent years, there has been steady progress in the creation of quantum computers. If large-scale quantum computers are implemented, they will threaten the security of many widely used public-key cryptosystems. Key-establishment schemes and digital signatures based on factorization, discrete logarithms, and elliptic curve cryptography will be most affected. Symmetric cryptographic primitives such as block ciphers and hash functions will be broken only slightly. As a result, there has been an intensification of research on finding public-key cryptosystems that would be secure against cryptanalysts with both quantum and classical computers. This area is often called post-quantum cryptography (PQC), or sometimes quantum-resistant cryptography. The goal is to design schemes that can be deployed in existing communication networks and protocols without significant changes. The National Institute of Standards and Technology is in the process of selecting one or more public-key cryptographic algorithms through an open competition. New public-key cryptography standards will define one or more additional digital signatures, public-key encryption, and key-establishment algorithms. It is assumed that these algorithms will be able to protect confidential information well in the near future, including after the advent of quantum computers. After three rounds of evaluation and analysis, NIST has selected the first algorithms that will be standardized as a result of the PQC standardization process. The purpose of this article is to review and analyze the state of NIST's post-quantum cryptography standardization evaluation and selection process. The article summarizes each of the 15 candidate algorithms from the third round and identifies the algorithms selected for standardization, as well as those that will continue to be evaluated in the fourth round of analysis. Although the third round is coming to an end and NIST will begin developing the first PQC standards, standardization efforts in this area will continue for some time. This should not be interpreted as meaning that users should wait to adopt post-quantum algorithms. NIST looks forward to the rapid implementation of these first standardized algorithms and will issue future guidance on the transition. The transition will undoubtedly have many complexities, and there will be challenges for some use cases such as IoT devices or certificate transparency.