Leakage-resilient certificateless public key encryption with equality test resistant to side-channel attacks

Public key encryption (PKE) has revolutionized modern cryptography, providing robust security for communication and data protection. However, traditional PKE schemes rely heavily on certificates, resulting in complex and inefficient certificates management problem. To address this problem, certificateless public key encryption (CL-PKE) was introduced to offer a more flexible and efficient approach for key distribution and management. While CL-PKE provides advancements in key management, it is unable to carry out equality tests on ciphertexts, which is essential for tasks such as verification of encrypted data (ciphertexts). To tackle this limitation, the integration of an equality test into CL-PKE, namely certificateless public key encryption with equality test (CL-PKEET), has been proposed. Recent discoveries have highlighted the insecurity of public-key systems due to side-channel attacks. To the best of our knowledge, no CL-PKEET scheme has been proposed to withstand such attacks. Hence, our objective is to present the first CL-PKEET scheme capable of withstanding side-channel attacks, which we call the leakage-resilient CL-PKEET (LR-CL-PKEET) scheme. The proposed scheme offers IND-CCA security and OW-CCA security. Furthermore, the scheme ensures robust security even in the presence of side-channel attacks.