Abstract: Certificateless generalized signcryption adaptively work as certificateless signcryption, signature or encryption scheme having single algorithm for suitable storage-constrained environments. Recently, Zhou et al. proposed a novel Certificates generalized scheme, and proved its ciphertext indistinguishability under adaptive chosen ciphertext attacks (IND-CCA2) using Gap Bi-linear Diffie-Hellman and Computational Diffie-Hellman assumption as well as proved existential unforgeability against chosen message attacks (EUF-CMA) using the Gap Bi-linear Diffie-Hellman and Computational Diffie-Hellman assumption in random oracle model. In this paper, we analyzed Zhou et al. scheme and unfortunately proved IND-CCA2 insecure in encryption and signcryption modes in defined security model. We also present a practical and improved scheme, provable secure in random oracle model.

Abdul Waheed, Jawaid Iqbal, Nizamud Din, Shahab Ul Islam, Arif Iqbal Umar and Noor Ul Amin, “Improved Cryptanalysis of Provable Certificateless Generalized Signcryption” International Journal of Advanced Computer Science and Applications(IJACSA), 10(4), 2019. http://dx.doi.org/10.14569/IJACSA.2019.0100475

@article{Waheed2019,
title = {Improved Cryptanalysis of Provable Certificateless Generalized Signcryption},
journal = {International Journal of Advanced Computer Science and Applications},
doi = {10.14569/IJACSA.2019.0100475},
url = {http://dx.doi.org/10.14569/IJACSA.2019.0100475},
year = {2019},
publisher = {The Science and Information Organization},
volume = {10},
number = {4},
author = {Abdul Waheed and Jawaid Iqbal and Nizamud Din and Shahab Ul Islam and Arif Iqbal Umar and Noor Ul Amin}
}