Hash functions play a fundamental role in cryptography, offering one-way and collision-resistant properties essential for digital security. Chameleon hashing, an extension of traditional hash functions, allows controlled collision generation using a private trapdoor, enabling various cryptographic applications such as online/offline digital signatures and commitment schemes. However, existing identity-based chameleon hash (IBCH) functions largely rely on number-theoretic assumptions, which are vulnerable to quantum attacks. To address this issue, we propose a novel IBCH function built upon post-quantum lattice-based cryptography. Specifically, our construction leverages the Short Integer Solution (SIS) problem to achieve quantum-resistant security guarantees. The proposed scheme enables identitybased key management, allowing users to generate hash values using public identity information while preserving the trapdoorcontrolled collision property. We rigorously analyze the security of our scheme, demonstrating its resistance against quantum adversaries under standard lattice assumptions. Furthermore, we compare our construction with existing functions in terms of computational efficiency and security, showing that our approach provides a feasible and secure alternative for post-quantum applications.
Hash functions play a fundamental role in cryptography, offering one-way and collision-resistant properties essential for digital security. Chameleon hashing, an extension of traditional hash functions, allows controlled collision generation using a private trapdoor, enabling various cryptographic applications such as online/offline digital signatures and commitment schemes. However, existing identity-based chameleon hash (IBCH) functions largely rely on number-theoretic assumptions, which are vulnerable to quantum attacks. To address this issue, we propose a novel IBCH function built upon post-quantum lattice-based cryptography. Specifically, our construction leverages the Short Integer Solution (SIS) problem to achieve quantum-resistant security guarantees. The proposed scheme enables identitybased key management, allowing users to generate hash values using public identity information while preserving the trapdoorcontrolled collision property. We rigorously analyze the security of our scheme, demonstrating its resistance against quantum adversaries under standard lattice assumptions. Furthermore, we compare our construction with existing functions in terms of computational efficiency and security, showing that our approach provides a feasible and secure alternative for post-quantum applications.
As a standard digital signature may be verified by anybody, it is unsuitable for personal or economically sensitive applications. The chameleon signature system was presented by Krawczyk and Rabin as a solution to this problem. It is based on a hash then sign model. The chameleon hash function enables the trapdoor information holder to compute a message digest collision. The holder of a chameleon signature is the recipient of a chameleon signature. He could compute collision on the hash value using the trapdoor information. This keeps the recipient from disclosing his conviction to a third party and ensures the privacy of the signature. The majority of the extant chameleon signature methods are built on the computationally infeasible number theory problems, like integer factorization and discrete log. Unfortunately, the construction of quantum computers would be rendered insecure to those schemes. This creates a solid requirement for construct chameleon signatures for the quantum world. Hence, this paper proposes a novel quantum secure chameleon signature scheme based on hash functions. As a hash-based cryptosystem is an essential candidate of a post-quantum cryptosystem, the proposed hash-based chameleon signature scheme would be a promising alternative to the number of theoretic-based methods. Furthermore, the proposed method is key exposure-free and satisfies the security requirements such as semantic security, non-transferability, and unforgeability.
Identity-based signature (IBS) which is a paradigm built on public key cryptography has played a significant role in light-weight authentication. With the advent of the post quantum era, the lattice has become a main mathematical tool to construct quantum-immune cryptographic schemes. By utilizing an admissible hash function with compatible algorithms and lattice trapdoors as basic building blocks, we propose a new IBS scheme over lattices. The scheme is proved existentially unforgeable against adaptive identity attacks and chosen message attacks in the standard model under inhomogeneous short integer solution assumption via the generalized partitioning proof technique. Moreover, the scheme needs only logarithmic basic matrices as master public key while keeping the same private key size and signature size as those of other standard model lattice-based IBS schemes. This construction is the first adaptive-ID secure standard model IBS scheme over lattice with such space efficiency.
The rapid advancement of quantum computing presents a fundamental challenge to modern cryptographic security, particularly in the domain of hash functions that ensure data integrity, authentication, and blockchain security. Traditional crypto graphic hash functions such as SHA-256, SHA-3, and BLAKE2 rely on computational hardness assumptions that become obsolete in the presence of large-scale quantum computers. Shor’s algorithm can efficiently break RSA and ECC-based cryptosys tems, while Grover’s algorithm reduces the security of traditional hash functions by square root complexity, significantly weakening their preimage and collision resistance. This quantum threat necessitates the development of post-quantum secure hashing techniques that remain resilient against both classical and quantum adversaries. This paper proposes Quantum Hashing, a novel cryptographic framework that integrates quantum entanglement, lattice-based cryptography, and hybrid quantum classical hashing to construct post-quantum secure hash functions. We introduce a formal model for Quantum Collision Resistance (QCR) and provide entropy-based ran domness enhancement to ensure unpredictable hash outputs. Unlike classical hashing approaches, our framework leverages the hardness of lattice problems (e.g., Shortest Vector Problem, Learning with Errors) to withstand quantum attacks while incorpo rating Quantum Key Distribution (QKD) mechanisms to enhance entropy and key management. Furthermore, we evaluate the security of Quantum Hashing under various attack models, comparing its resistance against Grover’s search and collision attacks. We benchmark its performance against NIST Post-Quantum Cryptography (PQC) final ists, including CRYSTALS-DILITHIUM, SPHINCS+, and Falcon, demonstrating that our approach offers superior resilience while maintaining computational feasibility. Additionally, we present an implementation of Quantum Hashing using Qiskit, show casing its practical applicability in quantum circuits and quantum-secure blockchain architectures. Our findings highlight that Quantum Hashing provides a scalable, entropy-efficient, and post-quantum resilient cryptographic primitive suitable for next-generation cryptographic applications. This work paves the way for secure post-quantum digital signatures, blockchain consensus mechanisms, and zero-knowledge proof systems that require tamper-resistant hashing in a quantum computing era.
Traditional digital signatures are often publicly verifiable, and in certain applications with privacy preservation requirements, the signer does not want the sensitive information it signed to be redelivered by a dishonest verifier.Aiming at the problem that traditional chameleon signatures (CS) cannot resist quantum computer attacks, this paper proposes a lattice-based authentication CS scheme.Based on the analysis of the lattice difficulty problem and the security vulnerability of the CS scheme, it is pointed out that it does not satisfy the third-party unforgeability and the signer rejectability, and a new lattice-based identity CS scheme is established, which is verified under the stochastic predicate machine model, and the storage and transmission efficiency of the scheme is analyzed.The results show that the newly designed identity-based CS scheme on the lattice can effectively resist quantum computer attacks, can sign messages of arbitrary length, and possesses more lightweight storage and transmission efficiency.The optimized chameleon signature scheme has better security and also provides a new solution for digital signatures to resist quantum computer attacks.
Inspired by Agrawal, Boneh and Boyen's identity-based encryption scheme, we proposed a post-quantum identity-based signature scheme from lattices. In this construction, two distinct trapdoors are used to find short bases. One trapdoor enables the real implementation to generate short bases for all lattices. The other trapdoor enables the simulator to generate short bases for all lattices. Moreover, the generating short bases are used to sample short vectors as signatures. Based on the hardness of the small integer solution (SIS) problem, the proposed scheme is proven to be strongly unforgeable against adaptive chosen-identity and adaptive chosen-message attacks without using random oracles. Compared with the existing strongly unforgeable identity-based signature schemes, our scheme has the advantages of full security and resistance to quantum computing attacks.
The need and emergence of quantum computing under National Quantum Mission threatens the cyber-security of existing cryptographic protocols, especially public-key schemes built on integer factorization and discrete logarithms. Lattice-based cryptography has gained prominence as a robust candidate for post-quantum cryptography—offering security against quantum attacks while enabling efficient operations, parallelization, and novel functionalities. This paper analyzes the mathematical foundations of lattices, explores hardness assumptions underlying widely studied lattice problems, highlights prominent cryptographic constructions, analyzes performance trade-offs, and reviews standardization efforts. This paper concludes by identifying ongoing issues and future directions for lattice-based cryptographic systems in a quantum-secure digital world. The algorithm has been implemented in Python.