Post-Quantum Signcryption From Lattice-Based Signatures.

Rownak Borhan, Yuzo Taenaka, Youki Kadobayashi

Johannes A Buchmann, Richard Lindner, Markus Rückert +1 more

Kunal Dey, Sumit Kumar Debnath, Pantelimon Stănică +1 more

Xiaojun Zhang, Chunxiang Xu, Chunhua Jin +1 more

Proxy-signcryption is a variation of an ordinary signcryption scheme and has been used in many applications where the delegation of rights is quite common. In a proxy-signcryption scheme, an original signcrypter needs to delegate his signcryption capability to a proxy signcrypter to signcrypt messages on behalf of the original signcrypter. By combining the functionalities of proxy signature with identity-based signcryption, in this paper, we propose a novel identity-based proxy-signcryption scheme (IBPSC) from lattice assumptions in the random oracle model. Meanwhile, the security requirements of our IBPSC scheme have been analysed, and our scheme can even resist quantum computer attacks. Compared with existing IBPSC schemes, our scheme is more secure and more efficient. To the best of our knowledge, there is still no relevant IBPSC scheme based on lattice, which is an interesting stepping stone in the post-quantum cryptographic communication.

Jianhua Yan, Licheng Wang, Yixian Yang +2 more

Signcryption is a cryptographic primitive that can perform digital signature and public encryption simultaneously at a significantly reduced cost. This advantage makes it highly useful in many applications. However, most existing signcryption schemes are seriously challenged by the booming of quantum computations. As an interesting stepping stone in the post-quantum cryptographic community, two lattice-based signcryption schemes were proposed recently. But both of them were merely proved to be secure in the random oracle models. Therefore, the main contribution of this paper is to propose a new lattice-based signcryption scheme that can be proved to be secure in the standard model.

Mostefa Kara, Mohammad Ali A. Hammoudeh, Abdullah Alamri +1 more

To ensure confidentiality and integrity in the era of quantum computing, most post-quantum cryptographic schemes are designed to achieve either encryption or digital signature functionalities separately. Although a few signcryption schemes exist that combine these operations into a single, more efficient process, they typically rely on complex vector, matrix, or polynomial-based structures. In this work, a novel post-quantum public-key encryption and signature (PQES) scheme based entirely on scalar integer operations is presented. The proposed scheme employs a simplified structure where the ciphertext, keys, and core cryptographic operations are defined over scalar integers modulo n, significantly reducing computational and memory overhead. By avoiding high-dimensional lattices or ring-based constructions, the PQES approach enhances implementability on constrained devices while maintaining strong security properties. The design is inspired by modified learning-with-errors (LWE) assumptions, adapted to scalar settings, making it suitable for post-quantum applications. Security and performance evaluations, achieving a signcryption time of 0.0007 s and an unsigncryption time of 0.0011 s, demonstrate that the scheme achieves a practical balance between efficiency and resistance to quantum attacks.