Leakage-resilient Identity-based Encryption Scheme Research Articles

Practical continuous leakage-resilient CCA secure identity-based encryption

Leakage of private information including private keys of user has become a threat to the security of computing systems. It has become a common security requirement that a cryptographic scheme should withstand various leakage attacks. In the real life, an adversary can break the security of cryptography primitive by performing continuous leakage attacks. Although, some research on the leakage-resilient cryptography had been made, there are still some remaining issued in previous attempts. The identity-based encryption (IBE) constructions were designed in the bounded-leakage model, and might not be able to meet their claimed security under the continuous-leakage attacks. In the real applications, the leakage is unbounded. That is, a practical cryptography scheme should keep its original security in the continuous leakage setting. The previous continuous leakage-resilient IBE schemes either only achieve chosen-plaintext attacks security or the chosen-ciphertext attacks (CCA) security is proved in the selective identity model. Aiming to solve these problems, in this paper, we show how to construct the continuous leakage-resilient IBE scheme, and the scheme’s adaptive CCA security is proved in the standard model based on the hardness of decisional bilinear Diffie-Hellman exponent assumption. For any adversary, all elements in the ciphertext are random, and an adversary cannot obtain any leakage on the private key of user from the corresponding given ciphertext. Moreover, the leakage parameter of our proposal is independent of the plaintext space and has a constant size.

Continuous Leakage-Resilient Identity-Based Encryption with Tight Security

Abstract In the actual applications, an adversary can break the security of cryptography scheme through various leakage attacks (e.g. side-channel attacks, cold-boot attacks, etc.), even the continuous leakage attacks. That is, a practical cryptography scheme must maintain its claimed security in the continuous leakage setting. However, the previous constructions on the leakage-resilient identity-based encryption (IBE) scheme could tolerate a leakage that is bounded, and cannot resist the continuous leakage attacks. In order to further achieve the better security, a novel method to build the continuous leakage-resilient IBE scheme with tight security is presented in this paper, and the scheme’s security is proved, in the standard model, based on a stronger security assumption that depends on the number of queries made by the adversary. In addition, our proposal has several advantages over previous such constructions, e.g. shorter public parameters, higher communication efficiency, tight security, etc.

A Leakage-Resilient CCA-Secure Identity-Based Encryption Scheme

Identity-based encryption (IBE) has many appealing applications. However, some traditional IBE schemes may not be secure in the real world due to the side-channel attacks. Leakage-resilient cryptography can capture these attacks by modeling information leakage that adversary can access. In this paper, we apply a hash proof technique in the existing CCA-secure variant of the Gentry's IBE scheme to construct a new leakage-resilient IBE scheme in the bounded-leakage model. The proposed scheme is more computationally efficient than the original Alwen et al. 's leakage-resilient IBE scheme. It enjoys a shorter key (public/secret key) length, and a higher relative key leakage ratio. The new leakage-resilient scheme is proved semantically secure against adaptive chosen ciphertext attack in the standard model under the truncated augmented bilinear Diffie-Hellman exponent ( |$q$| -TABDHE) assumption.