It is assumed that certain mathematical or computational problems which are used in traditional cryptographic schemes are hard to solve for an attacker using today’s computers. But, lots of companies are trying to build quantum computer and in coming few years commercial quantum computer will be in reality. Security of traditional asymmetric cryptographic algorithms can be broken using quantum computers. So, researchers all over the world are planning for transition to post-quantum cryptography. One solution is to build hybrid solution combining both traditional and post-quantum primitives which will provide traditional cryptographic guarantees as well as quantum resistance [1].The best and feasible hybrid solution can be used in the protocols like SSL/TLS, SSH and PGP.
It is assumed that certain mathematical or computational problems which are used in traditional cryptographic schemes are hard to solve for an attacker using today’s computers. But, lots of companies are trying to build quantum computer and in coming few years commercial quantum computer will be in reality. Security of traditional asymmetric cryptographic algorithms can be broken using quantum computers. So, researchers all over the world are planning for transition to post-quantum cryptography. One solution is to build hybrid solution combining both traditional and post-quantum primitives which will provide traditional cryptographic guarantees as well as quantum resistance [1].The best and feasible hybrid solution can be used in the protocols like SSL/TLS, SSH and PGP.
Post Quantum Cryptography (sometimes referred to as a quantum-proof, quantum-safe or quantum-resistant) refers to cryptographic algorithms (usually public-key algorithms) that are thought to be secure against an attack by a quantum computer. PQC is all about preparing for the era of quantum computing by updating existing mathematical-based algorithms and standards. The cryptographic community is working on post-quantum cryptography in order to provide alternatives using hard mathematical problems that cannot be broken by quantum computers. A hybrid scheme is recommended to ease the transition into the post-quantum era. A hybrid scheme is a combination of a traditional and a post-quantum scheme. The resulting scheme is at least as secure as one of the schemes used. In hybrid key establishment, two independent key exchanges are performed one with a traditional scheme like ECDHE and one with a post-quantum scheme like NewHope [1]. In this paper, we propose possible best-fit hybrid digital signatures.
The advent of quantum computing poses a significant threat to the foundational cryptographic algorithms that secure modern digital communications. [27]. Protocols such as HTTPS, digital certificates, and public key infrastructures (PKIs) heavily rely on cryptographic primitives like RSA, ECC, and Diffie-Hellman, which are vulnerable to quantum attacks—most notably Shor’s algorithm. [18]. This paper presents a comprehensive comparative analysis between classical cryptographic algorithms currently in widespread use and emerging post-quantum cryptographic schemes designed to withstand quantum adversaries. [24]. We review the cryptographic mechanisms underpinning modern internet security, outline the mathematical foundations of quantum attacks, and evaluate the security, performance, and implementation feasibility of quantum-resistant alternatives such as Kyber, Dilithium, and Falcon. [25]. Additionally, we assess the hybrid approaches currently being explored by institutions and tech companies to enable a smooth transition to post-quantum cryptography. [23]. By providing an in-depth comparison, this study aims to guide researchers, developers, and policymakers in understanding the critical implications of quantum computing on cryptographic infrastructures and the necessary steps for securing communications in the quantum era. [16].
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 last few years the threat of quantum computers has become bigger and bigger. The fast computing of the quantum computers puts everything in danger that relies on classical cryptographic algorithms. The question of when a large-scale quantum computer will be built cannot be exactly answered yet. According to the Cloud Security Alliance at around 2030 the power of quantum computers will increase so that the risk for exposure of traditionally encrypted data will be very high. PKI (Public Key Infrastructure) relies on asymmetric cryptographic algorithms and is widely used in many fields. So it is important that it will be completely safe. The way to provide that is to change traditional cryptographic algorithms to post-quantum cryptography algorithms or hybrid solutions. To this, we review in this paper the basics of classical PKI and quantum cryptography methods and the threat of quantum computing for PKI. We present quantum-safe solutions already in use and recommend new, well-performing solutions for a quantum-resistant PKI by comparison.
Many companies are working to build a powerful quantum computer.Once quantum computer with large qubits is reality, asymmetric-key cryptosystem will be vulnerable for Shor's algorithm.The transition from one cryptosystem to another is very slow process and consumes many years.National Institute of Standards and Technology (NIST) is working on standardization of post-quantum cryptographic (PQC) algorithms.Security of current PQC algorithms cannot be fully verified today.So, in coming years we need to rely on both traditional algorithms and PQC algorithms.Hybrid mode consisting of one traditional algorithm and one post quantum algorithm is a best solution for smooth migration to quantum-safe cryptosystem.For key exchange, it means using two or more key exchange encapsulation algorithms for generating session key [Meher and Midhunchakkaravarthy (2019)].For authentication, it means using two or more digital signature algorithms [Meher and Midhunchakkaravarthy (2019)].There are number of approaches to combine secret key from traditional algorithm and PQC algorithm to make key encapsulation mechanism quantum-proof.In the paper we propose a new approach of using secret master key generated from one of the KEM algorithm as a salt for hashbased key derivation function (HKDF) to drive session keys from secret master key generated from another KEM algorithm.
Broken cryptographic algorithms and hardness assumptions are a constant threat to real-world protocols. Prominent examples are hash functions for which collisions become known, or number-theoretic assumptions which are threatened by advances in quantum computing. Especially when it comes to key exchange protocols, the switch to quantum-resistant primitives has begun and aims to protect today’s secrets against future developments, moving from common Diffie–Hellman-based solutions to Learning-With-Errors-based approaches, often via intermediate hybrid designs.