Certificateless public-key cryptography has conquered both the certificate management problem in the traditional public-key cryptography and the key escrow problem in the ID-based public-key cryptography. Certificateless authenticated key exchange (CLAKE) protocol is an important primitive of the certificateless public-key cryptography. A CLAKE protocol is employed to provide both mutual authentication and establishing a session key between two participators. Indeed, all conventional public-key cryptographies have encountered a new kind of attack, named “side-channel attacks”. Fortunately, leakage-resilient cryptography is a flexible approach to withstand such attacks. However, the design of leakage-resilient CLAKE (LR-CLAKE) protocols is not studied. In the article, by extending the well-known extended-Canetti-Krawczyk (eCK) model, we present the security notions (adversary model) of LR-CLAKE protocols, called continual-leakage-resilient eCK (CLReCK) model. The first LR-CLAKE protocol withstanding side-channel attacks is proposed. By employing the proof technique of the generic bilinear group (GBG) model, we formally prove the security of our protocol in the CLReCK model.
Certificateless public-key cryptography has conquered both the certificate management problem in the traditional public-key cryptography and the key escrow problem in the ID-based public-key cryptography. Certificateless authenticated key exchange (CLAKE) protocol is an important primitive of the certificateless public-key cryptography. A CLAKE protocol is employed to provide both mutual authentication and establishing a session key between two participators. Indeed, all conventional public-key cryptographies have encountered a new kind of attack, named “side-channel attacks”. Fortunately, leakage-resilient cryptography is a flexible approach to withstand such attacks. However, the design of leakage-resilient CLAKE (LR-CLAKE) protocols is not studied. In the article, by extending the well-known extended-Canetti-Krawczyk (eCK) model, we present the security notions (adversary model) of LR-CLAKE protocols, called continual-leakage-resilient eCK (CLReCK) model. The first LR-CLAKE protocol withstanding side-channel attacks is proposed. By employing the proof technique of the generic bilinear group (GBG) model, we formally prove the security of our protocol in the CLReCK model.
Identity-based authenticated key exchange (ID-AKE) protocol is an important cryptographic primitive, which is used to establish a session key between two communication participants while authenticating each other. Indeed, most of the existing ID-AKE protocols do not concern with side-channel attacks in the sense that adversaries could obtain partial information of ephemeral/permanent secret keys of users. Recently, several leakage-resilient ID-AKE (LR-ID-AKE) protocols have been proposed to address such attacks. However, these LR-ID-AKE protocols have a restriction that the total leakage information during the life time of the LR-ID-AKE protocol must be bounded to some ratio of ephemeral/permanent secret keys. In this paper, the authors define a new adversary model, termed as identity-based continuous-leakage extended Canetti-Krawczyk (ID-CL-eCK) model. Using the key refreshing procedure (i.e., the multiplicative blinding technique) of permanent secret keys, the first LR-ID-AKE protocol resilient to continuous key leakage is proposed, and it possesses overall unbounded leakage property. Comparisons are given to demonstrate that the proposed protocol is better than the previously proposed ID-AKE protocols in terms of security models and leakage properties. Under the generic bilinear group model, security analysis is made to show that the proposed LR-ID-AKE protocol is secure against adversaries in the new ID-CL-eCK model.
Certificate-based public key cryptography (CB-PKC) removes the problem of certificate management in traditional public key systems and avoids the key escrow problem in identity-based public key systems. In the past, many authenticated key exchange (AKE) protocols based on CB-PKC systems, called CB-AKE, were proposed to be applied to secure communications between two remote participants. However, these existing CB-AKE protocols become insecure since attackers could compute and obtain the whole secret key from some partial leaked information of the secret key by side channel attacks. In this paper, our goal is to propose thefirstCB-AKE protocol with the property to resist side channel attacks, called leakage-resilient CB-AKE (LR-CB-AKE). The proposed LR-CB-AKE protocol is formally proven to be secure in the generic bilinear group (GBG) model under the discrete logarithm (DL) and computational Diffie-Hellman (CDH) assumptions.
Based on users’ permanent private keys and ephemeral secret keys (randomness secret values), authenticated key agreement (AKA) protocols are used to construct a common session key between two session parties while authenticating each other. Recently, the design of leakage-resilient AKA (LR-AKA) resisting side-channel attacks has received significant attention from researchers. By side-channel attacks, an adversary is allowed to obtain fractional leakage information of private (secret) keys during the computation rounds of LR-AKA protocols. However, most LR-AKA protocols have a restriction, namely, the overall fractional leakage information must be bounded. In this paper, we propose an efficient LR-AKA protocol with overall unbounded leakage property in the continual leakage extended Canetti-Krawczyk model. Security analysis is given to demonstrate that our LR-AKA protocol is provably secure in the generic bilinear group model. By comparisons, our protocol is better than the previously proposed LR-AKA protocols in terms of computation cost, security model, and leakage properties.
Establishing a session key (SSK) is very important for real-world deployment in open networks, which enables secure communication between remote parties. In the past, some authenticated key exchange (AKE) protocols have been proposed to generate a SSK, but the certificate management issue is inhered in the traditional public key infrastructure and must be addressed. To tackle this issue, the identity (ID)-based concept is added to AKE, called ID-AKE. Indeed, the security of the existing AKE/ID-AKE protocols is gaining increasing importance due to some new types of attacks, namely, side-channel attacks. In such attacks, adversaries could obtain secret keys’ partial information during the execution of cryptographic protocols (including AKE/ID-AKE). To withstand such attacks, many leakage-resilient ID-AKE (LR-ID-AKE) protocols resisting side-channel attacks have been proposed. However, these existing LR-ID-AKE protocols have no efficient solution to revoke compromised users. In this article, the first LR-ID-AKE protocol with an efficient revocation mechanism, called LR-RID-AKE, is proposed. The proposed protocol is not only as secure as existing LR-ID-AKE protocols but also able to efficiently revoke compromised users from the system.
In public-key cryptography (PKC), a signcryption (SC) scheme is a significant primitive by combining both signature and encryption functionalities in one scheme while reducing computing time. Most SC schemes are based on single PKC setting, such as public-key infrastructure PKC (PKI-PKC), identity-based PKC (ID-PKC), certificate-based PKC (CB-PKC), and certificateless PKC (CL-PKC). For providing practical usage, numerous hybrid SC (HSC) schemes were also presented to suit for the sense that a sender and a recipient belong to different PKC settings (i.e., heterogeneous PKC settings). Recently, side-channel attacks have been realized to endanger the existing SC and HSC schemes. Indeed, the research of leakage-resilient cryptography resistant to side-channel attacks have attracted the attention of researchers. Indeed, several SC schemes with leakage resilience (SC-LR) based on single PKC setting have been proposed. However, little research focuses on HSC scheme with leakage-resilience (HSC-LR). Therefore, this paper aims to design the first HSC-LR from senders under a CB-PKC setting to recipients under a PKI-PKC setting, called as the HSC-LR-CBPKI scheme. We formally define a new framework and two security games of the HSC-LR-CBPKI scheme. Two security theorems are proved that the HSC-LR-CBPKI scheme possesses both signature and encryption functionalities (including unforgeability and confidentiality) under side-channel attacks. Finally, the proposed scheme is very efficient by performance analysis.
Leakage attacks, including various kinds of side-channel attacks, allow an attacker to learn partial information about the internal secrets such as the secret key and the randomness of a cryptographic system. Designing a strong, meaningful, yet achievable security notion to capture practical leakage attacks is one of the primary goals of leakage-resilient cryptography. In this work, we revisit the modelling and design of authenticated key exchange (AKE) protocols with leakage resilience. We show that the prior works on this topic are inadequate in capturing realistic leakage attacks. To close this research gap, we propose a new security notion named leakage-resilient eCK model w.r.t. auxiliary inputs (AI-LR-eCK) for AKE protocols, which addresses the limitations of the previous models. Our model allows computationally hard-to-invert leakage of both the long-term secret key and the randomness, and also addresses a limitation existing in most of the previous models where the adversary is disallowed to make leakage queries during the challenge session. As another major contribution of this work, we present a generic framework for the construction of AKE protocols that are secure under the proposed AI-LR-eCK model. An instantiation based on the decision Diffie–Hellman (DDH) assumption in the standard model is also given to demonstrate the feasibility of our proposed framework.