Leakage-Resilient Public Key Encryption with Equality Test Resistant to Side-channel Attacks

Abstract

Public key encryption (PKE) plays a crucial role in protecting sensitive information. It allows the use of a pair of keys - a public key and a secret key. The public key can be shared with anyone for encrypting messages, but only the secret key can decrypt these messages. However, traditional PKE schemes only support basic cryptographic operations such as encryption and decryption, and do not provide additional functionality such as equality test. Public key encryption with equality test (PKEET) is an extension of PKE that allows a third party to verify if two ciphertexts, encrypted using distinct public keys, originate from the same plaintext. Notably, this verification is performed while ensuring that the third party remains oblivious to the actual plaintext. In computer security, side-channel attacks are a common type of attacks that typically involves attacking the physical implementation of cryptographic algorithms, such as measuring the power consumption of a computer chip, electromagnetic radiation, clock skew, etc., to extract cryptographic keys or sensitive information. The severity of side-channel attacks lies in the fact that attackers do not need to break the cryptographic algorithm to obtain sensitive information but instead exploit the physical implementation of the algorithm. To the best of our knowledge, there is currently no existing PKEET that is capable of resisting side-channel attacks. Therefore, the objective of this paper is to propose the first leakage-resilient public key encryption with equality test (LR-PKEET) that can resist side-channel attacks.