Master-key leakage-resilient and continue leakage-resilient functional encryption in dual affine spaces

A leakage-resilient cryptosystem considers that an attacker is able to learn partial information about some values used throughout the lifetime of the system. Leakage-resilient encryption guarantees that the scheme is semantically secure even though the attacker has the abilities in obtaining bounded private keys and/or master keys. In this paper, we propose a leakage-resilient functional encryption in dual affine spaces that encryption policies and decryption roles are specified as affine (sub) spaces. Also, both encryption policies and decryption roles can perform delegation functionalities, which are flexible and expensive in practical applications. The proposed scheme can tolerant the bounded leakage in masters keys and private keys. We prove the security under the static subgroup decision assumptions in the standard model. Meanwhile, we analyze the tolerant bound and leakage ratio, and benefit the property of fine-grained leakage resilience.