Abstract. We introduce the concept of attribute-based authenticated key exchange (AB-AKE) within the framework of ciphertext policy attribute-based systems. A notion of AKE-security for AB-AKE is presented based on the security models for group key exchange protocols and also taking into account the security requirements generally considered in the ciphertext policy attribute-based setting. We also extend the paradigm of hybrid encryption to the ciphertext policy attribute-based encryption schemes. A new primitive called encapsulation policy attribute-based key encapsulation mechanism (EP-AB-KEM) is introduced and a notion of chosen ciphertext security is defined for EP-AB-KEMs. We propose an EP-AB-KEM from an existing attribute-based encryption scheme and show that it achieves chosen ciphertext security in the generic group and random oracle models. We present a generic one-round AB-AKE protocol that satisfies our AKE-security notion. The protocol is generically constructed from any EP-AB-KEM that satisfies chosen ciphertext security. Instantiating the generic AB-AKE protocol with our EP-AB-KEM will result in a concrete one-round AB-AKE protocol also secure in the generic group and random oracle models.
Abstract. We introduce the concept of attribute-based authenticated key exchange (AB-AKE) within the framework of ciphertext policy attribute-based systems. A notion of AKE-security for AB-AKE is presented based on the security models for group key exchange protocols and also taking into account the security requirements generally considered in the ciphertext policy attribute-based setting. We also extend the paradigm of hybrid encryption to the ciphertext policy attribute-based encryption schemes. A new primitive called encapsulation policy attribute-based key encapsulation mechanism (EP-AB-KEM) is introduced and a notion of chosen ciphertext security is defined for EP-AB-KEMs. We propose an EP-AB-KEM from an existing attribute-based encryption scheme and show that it achieves chosen ciphertext security in the generic group and random oracle models. We present a generic one-round AB-AKE protocol that satisfies our AKE-security notion. The protocol is generically constructed from any EP-AB-KEM that satisfies chosen ciphertext security. Instantiating the generic AB-AKE protocol with our EP-AB-KEM will result in a concrete one-round AB-AKE protocol also secure in the generic group and random oracle models.
Several protocols implementing attribute-based group key exchange, which allows users with certain set of attributes to establish a session key, have been proposed in recent years.However, attacks on attribute-based group key exchange in current research have been considered only in stand-alone fashion.Thus these protocols may be vulnerable when run with other protocol sessions concurrently.We treat the security of attribute-based group key exchange in the universal composability framework to ensure that a protocol remains secure when run with arbitrary protocol sessions concurrently.More specifically, we define an ideal functionality for attribute-based group key exchange first, then propose a two-round protocol based on a primitive called encapsulation policy attribute-based key encapsulation mechanism.In addition, a complete security proof of our protocol in the universal composability framework under random oracle model is given. Encapsulation Policy Attribute-based Key Encapsulation Mechanism (EP-AB-KEM)The EP-AB-KEM introduced by Gorantla et al. and used by our protocol follows the framework of ciphertext policy attribute based encryption (CP-ABE).An EP-AB-KEM consists of five probabilistic polynomial time algorithm listed below.(1) Setup: inputs system security parameter and attribute universe description, then outputs system public parameters PK and system master key MK.
Attribute-based authenticated key exchange (AB-AKE) is a useful primitive that allows a group of users to establish a shared secret key and at the same time enables fine-grained access control. A straightforward approach to design an AB-AKE protocol is to extend a key exchange protocol using an attribute-based authentication technique. However, insider security is a challenge security issue for AB-AKE in the multi-party setting and cannot be solved using the straightforward approach. In addtion, many existing key exchange protocols for the multi-party setting (e.g., the well-known Burmester-Desmedt protocol) require multiple broadcast rounds to complete the protocol. In this paper, we propose a novel one-round attribute-based key exchange (OAKE) protocol in the multi-party setting. We define the formal security models, including session key security, insider security and user privacy, for OAKE, and prove the security of the proposed protocol under some standard assumptions in the random oracle model.
In this paper, we propose a generic construction of one-round attribute-based (implicitly) authenticated key exchange (ABAKE). The construction is based on a chosen-ciphertext (CCA) secure attribute-based KEM and the decisional Diffie-Hellman (DDH) assumption. If an underlying attribute-based KEM scheme allows expressive access controls and is secure in the standard model (StdM), an instantiated ABAKE scheme also achieves them. Our scheme enjoys the best of both worlds: efficiency and security. The number of rounds is one (optimal) while the known secure scheme in the StdM is not one-round protocol. Our scheme is comparable in communication complexity with the most efficient known scheme that is not proved in the StdM. Also, our scheme is proved to satisfy security against advanced attacks like key compromise impersonation.
This paper firstly provides the extended Canetti-Krawzcyk (eCK) security model for predicate-based authenticated key exchange (AKE) that guarantees resistance to leakage of ephemeral secret keys. Moreover, we propose two-pass key-policy (resp. session-policy) attribute-based AKE protocol secure in the proposed predicate-based eCK security model based on key-policy (resp. ciphertext-policy) attribute-based encryption. The proposed protocols have advantages in security against leakage of ephemeral secret keys and the round complexity compared to the previous predicate-based AKE protocols.
How to reduce communication complexity is a common important issue to design cryptographic protocols. This paper focuses on authenticated key exchange (AKE). Several AKE schemes have been studied, which satisfy strong security such as exposure-resilience in the standard model (StdM). However, there is a large gap on communication costs between schemes in the StdM and in the random oracle model. In this paper, we show a generic construction that is significantly compact (i.e., small communication cost) and secure in the StdM. We follow an existing generic construction from key encapsulated mechanism (KEM). Our main technique is to use a bounded chosen-ciphertext secure KEM instead of an ordinary chosen-ciphertext secure KEM. The communication cost can be reduced to half by this technique, and we achieve the most compact AKE scheme in the StdM. Moreover, our construction has instantiations under wider classes of hardness assumptions (e.g., subset-sum problems and multi-variate quadratic systems) than existing constructions. This work pioneers the first meaningful application of bounded chosen-ciphertext secure KEM.
Abstract. An unresolved problem in research on authenticated key exchange (AKE) is to construct a secure protocol against advanced attacks such as key compromise impersonation and maximal exposure attacks without relying on random oracles. HMQV, a state of the art AKE protocol, achieves both efficiency and the strong security proposed by Krawczyk (we call it the CK + model), which includes resistance to advanced attacks. However, the security proof is given under the random oracle model. We propose a generic construction of AKE from a key encapsulation mechanism (KEM). The construction is based on a chosen-ciphertext secure KEM, and the resultant AKE protocol is CK + secure in the standard model. The construction gives the first CK + secure AKE protocols based on the hardness of integer factorization problem, code-based problems, or learning problems with errors. In addition, instantiations under the Diffie-Hellman assumption or its variant can be proved to have strong security without non-standard assumptions such as πPRF and KEA1. Furthermore, we extend the CK + model to identity-based (called the id-CK + model), and propose a generic construction of identity-based AKE (ID-AKE) based on identity-based KEM, which satisfies id-CK + security. The construction leads first strongly secure ID-AKE protocols under the hardness of integer factorization problem, or learning problems with errors.