Post-quantum cryptography (PQC) is a family of cryptographic algorithms that run on classical computers, but are resistant to cryptanalytic attacks on current private and public-key algorithms, via both classical and quantum computers. Post-quantum cryptography is also referred to as quantum-resistant or quantum-safe cryptography.
Abstract Large-scale and error-tolerant quantum computers will break the currently used tools for enabling confidentiality and integrity on the internet and elsewhere. It has been recognized for the last 10 years that there is an urgent need to develop cryptosystems that can withstand an attacker in the future with a quantum computer. Post-quantum cryptography (PQC), also sometimes known as quantum-resistant cryptography or quantum safe cryptography, means cryptographic algorithms that can run on today’s computers and networks and yet be secure against attackers in the future who have large-scale and error-tolerant quantum computers. This chapter will argue that post-quantum cryptography is more practical and trusted for most real-world systems than quantum key distribution (QKD). The purpose of this chapter is to put cryptography into the broader context of cybersecurity, to briefly explain the threats and risks associated with quantum computing, and to give a nontechnical overview of the post-quantum cryptosystems that are available now.
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.
Quantum-resistant cryptography is cryptography that aims to deliver cryptographic functions and protocols that remain secure even if large-scale fault-tolerant quantum computers are built. NIST will soon announce the first selected public-key cryptography algorithms in its Post-Quantum Cryptography (PQC) standardization which is the most important current effort in the field of quantum-resistant cryptography. This report provides an overview to security experts who do not yet have a deep understanding of quantum-resistant cryptography. It surveys the computational model of quantum computers; the quantum algorithms that affect cryptography the most; the risk of Cryptographically Relevant Quantum Computers (CRQCs) being built; the security of symmetric and public-key cryptography in the presence of CRQCs; the NIST PQC standardization effort; the migration to quantum-resistant public-key cryptography; the relevance of Quantum Key Distribution as a complement to conventional cryptography; and the relevance of Quantum Random Number Generators as a complement to current hardware Random Number Generators.
With the constantly changing world of computers nowadays, the introduction of quantum computing has posed immense threats to the security of old and previous encryption algorithms. Post-Quantum Cryptography or PQC refers to a new generation of algorithms specifically created to resist the intense quantum computer attacks and offer secure and long-lasting protection to digital communications. As the potential of quantum technology becomes increasingly evident, the pursuit of secure, future-proof cryptographic solutions has never been more critical. This systematic review explores different PQC solutions for their strengths, weaknesses, and challenges of implementation. provides a comprehensive analysis of key studies on quantum-resistant algorithms, migration strategies and examines cryptographic security measures to present a complete picture of the latest advancements in quantum-safe cryptography. In this systematic paper, different PQC algorithms such as lattice, hash, code, multivariate and isogeny are reviewed along with their advantages and disadvantages. It also discusses how such findings will affect the security of real world communication, digital signatures, as well as blockchain security. This ensures how important it is to establish standardized PQC protocols for overall data security. This paper concludes with what future research directions and practical considerations relate to the adoption of PQC in critical infrastructures.
The threats are existential to the traditional cryptosystems of public keys, including RSA, Diffie-Hellman, and elliptic curve cryptography (ECC), due to the rapid progress in quantum computing. Such algorithms as the Shor and Grover algorithms prove that as soon as large scale quantum computers are achieved, these classical cryptographic protocols will not provide any privacy and integrity to online communication. This has created an emergency to find post-quantum cryptography (PQC), or quantum-safe cryptography, which will resist attacks by both classical and quantum attackers. The paper is a review of the latest research and development in post-quantum cryptographic algorithms and their implementation in current security systems. We organize quantum-safe methods into significant organizations such as lattice-based, hash-based, multivariate polynomial-based and code-based encrypted communications. Each type has been evaluated critically based on computational efficiency, key sizes, speed of encryption/decryption and security proofs. The survey also examines the current standardization activities happening in the world and especially the U.S. National Institute of Standards and Technology (NIST) PQC competition, which lists candidate algorithms that have advanced to standard adoption. Besides this, the paper addresses hybrid cryptographic designs that use both classical and post-quantum bases in ensuring a seamless migration in the transition phase. Internet security protocols like TLS, VPNs and blockchain consensus as applications of PQC are examined in detail. Lastly, we pinpoint open research issues, which include creating lightweight PQC to support resource-constrained IoT devices, balancing performance and strong security assurances, and interoperability between the new PQC algorithms and existing infrastructures. Through detailed survey we inform the future of researchers, practitioners, and policymakers on the preparation of the post-quantum era of secure digital communications.
As quantum computing advances, current cryptographic protocols are increasingly vulnerable to quantum attacks, particularly those based on Public Key Infrastructure (PKI) like RSA or Elliptic Curve Cryptography (ECC). This paper presents a comprehensive review of Post-Quantum Cryptography (PQC) as a solution to protect digital systems in the quantum era. We provide an in-depth analysis of various quantum-resistant cryptographic algorithms, including lattice-based, code-based, hash-based, isogeny-based, and multivariate approaches. The review highlights the National Institute of Standards and Technology (NIST) PQC standardization process, highlighting key algorithms, such as CRYSTALS–Kyber, CRYSTALS–Dilithium, Falcon, and SPHINCS+, and discusses the strengths, vulnerabilities, and implementation challenges of the leading algorithms. In addition, we explore transition strategies for organizations, emphasizing hybrid cryptography to ensure backward compatibility during migration. This study offers key insights into the future of cryptographic standards and the critical steps necessary to prepare for the transition from classical to quantum-resistant systems.