Using multiple, individual encryption schemes is a well-established method to increase the overall security of encrypted data. These so-called multiple encryption or hybrid schemes have regained traction in the context of public-key cryptography due to the rise of quantum computers, since it allows the combination of well-known classical encryption schemes with novel post-quantum schemes. In this paper, we conduct a survey of the state-of-the-art public-key multiple encryption (M-PKE) schemes. For the first time, we describe the most relevant M-PKE schemes in detail and discuss their security in a unified model, which allows better comparison between the schemes. Hence, we compare the security, efficiency, and complexity of the schemes and offer recommendations for usage based on common use cases. Our survey emphasizes the importance of being deliberate when combining encryption schemes, as small nuances can easily break security.
Using multiple, individual encryption schemes is a well-established method to increase the overall security of encrypted data. These so-called multiple encryption or hybrid schemes have regained traction in the context of public-key cryptography due to the rise of quantum computers, since it allows the combination of well-known classical encryption schemes with novel post-quantum schemes. In this paper, we conduct a survey of the state-of-the-art public-key multiple encryption (M-PKE) schemes. For the first time, we describe the most relevant M-PKE schemes in detail and discuss their security in a unified model, which allows better comparison between the schemes. Hence, we compare the security, efficiency, and complexity of the schemes and offer recommendations for usage based on common use cases. Our survey emphasizes the importance of being deliberate when combining encryption schemes, as small nuances can easily break security.
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.
Quantum public-key encryption (PKE), where public-keys and/or ciphertexts can be quantum states, is an important primitive in quantum cryptography. Unlike classical PKE (e.g., RSA or ECC), quantum PKE can leverage quantumsecure cryptographic assumptions or the principles of quantum mechanics for security. It has great potential in providing for secure cryptographic systems under potentially weaker assumptions than is possible classically. In addition, it is of both practical and theoretical interest, opening the door to novel cryptographic systems not possible with classical information alone. While multiple quantum PKE schemes have been proposed, they require a large number of qubits acting coherently, and are not practical on current noisy quantum devices. In this paper, we design a practical quantum PKE scheme, taking into account the constraints of current NISQ devices. Specifically, we design a PKE scheme with quantum-classical public keys and classical ciphertexts, that is noise-resilient and only requires a small number of qubits acting coherently. In addition, our design provides tradeoffs in terms of efficiency and the number of qubits that are required.
The use of public key cryptosystems range from securely encrypting emails and files to creating digital signatures for non-repudiation. The security of public key cryptosystems is based on computationally "unsolvable" complex mathematical problems. This tends to change with the introduction of quantum computers that undoubtedly pose a threat to the current schemes. In response to that extensive research has been conducted that resulted in several cryptosystems that are believed to be quantum resistant. This thesis presents a concise overview of multiple hash-based signature schemes and provides a comparative description and analysis of them. The comparisons are based on different signature scheme properties, such as key sizes, signature sizes and security level provided. The proposed quantum resistant schemes are also compared to the standard schemes used today, such as RSA and ECDSA.
The accelerated advancements in quantum computing substantially threaten classical cryptographic systems, particularly those that rely on RSA, ECC, and other public key encryption methods. Particularly Shor's method shows how easily conventional cryptographic techniques might be broken; therefore quick development of quantum resistant substitutes is necessary. Rising as a potential answer with cryptographic algorithms meant to resist quantum attacks is post quantum cryptography (PQC). Nonetheless, performance trade-offs, compatibility problems, and the absence of standardized implementations make the shift to completely quantum-safe cryptographic systems very difficult. Hybrid PQC systems that combine conventional and quantum resistant cryptographic mechanisms have been suggested as a workable method for tackling these difficulties so guaranteeing security in the post quantum future. Emphasizing their security, performance, and practical implementations, this review article offers a thorough study of hybrid PQC methods. The resistance of many hybrid cryptographic models including lattice-based, code-based, and multivariate cryptographic techniques against quantum attacks is comprehensively investigated in this work methodologically, we review current PQC hybrid models, evaluate their computing efficiency, and examine security criteria grounded on recent research and standardizing initiatives like those under NIST. Our results show that hybrid PQC models create difficulties in terms of key management, computational overhead, and implementation complexity even if they improve security by reducing risks related with both conventional and quantum attacks. A comparative study shows among several hybrid systems the trade-offs in terms of encryption speed, key sizes, and resource use. Moreover showing the feasibility of PQC hybridizing in IoT, cloud computing, and block chain security are pragmatic uses of PQC hybridizing in which case appropriate protocols are needed for broad acceptance. At last, our work emphasizes the significant contribution hybrid PQC models provide in the transitional period producing a quantum secure environment. To enable basic integration into the present digital infrastructure, future research should focus on improving the efficiency of hybrid cryptosystems, optimizing key exchange mechanisms, and regulating standardization concerns. The findings of this study support the present discussion on post quantum security and provide data for academics and corporate leaders aiming for the next generation of cryptographic solutions. https://doi.org/10.5281/zenodo.17873992
In the quantum era, the advent of quantum computers poses significant threats to the security of current cryptosystems. Therefore, designing quantum-resistant cryptoschemes becomes important to guarantee information security. This work concentrates on the development of the post-quantum public key encryption (PKE) scheme. Non-commutative cryptography (NCC) has entered the field of post-quantum cryptography. We utilize the TSPEM problem with asymmetric structures (which serve as a potential candiate for resisting quantum attacks) to construct two PKE schemes which are demonstrated to be CPA security under the DTSPEM assumption. By representing the plaintext as a matrix, these schemes can effectively encrypt a significant amount of information in a single operation. Assuming an equal amount of messages for encryption, the proposed schemes acheive superior efficiency compared to existing PKE schemes. Structurally, our systems exhibit a level of synchronization and coexistence due to the distinct public keys $ (P) $ and ciphertexts $ (C_{1}) .Theefficiencyanalysisisconductedbycomparingknownschemesfromtheaspectofspecificcryptographicindicators.Generally,theproposedonesofferseveraladvantagesincludingprovablesecurity,highefficiency,potentialquantum−resistant,andrelativeeaseofimplementation;alongwithsynchronizationandcoexistence.OurinvestigationhasestablishedthefeasibilityofconstructingPKEschemesbasedontheTSPEMproblem,specificallyforasymmetriccommunicationscenarios.ThepreliminaryresultspavethewayforfurtherexplorationoftheTSPEMproblem ' $s potential in developing other cryptosystems suitable for quantum computing environments.
Cryptography has been in existence since before the advent of computers. It encompasses a variety of techniques designed to secure information, whether it is at rest or in transit. Symmetric key cryptography includes symmetric keys, which serve the dual purpose of encrypting and decoding communications. Descriptions have been provided for public/private key pairs, also known as asymmetric keys. Such pairs may be categorized as secret/public key pairs, where the private key remains confidential, while the public key is accessible to all relevant parties for communication and information exchange. The realm of private and public key cryptography is diverse. Recently, the National Institute of Standards and Technology (NIST) endorsed four post-quantum cryptography systems. This paper presents a comprehensive survey of cryptography, examining the implications of intricate cryptographic systems on our existing networks.