Authenticated Group Key Agreement Research Articles

An Authenticated Clustering-based Group Key Agreement for Large Ad Hoc Networks

Group key agreement protocols for wired networks are not applicable in ad hoc networks because of the 1-hop assumption of these protocols and the dynamic, multi-hop attributes of ad hoc networks. An authenticated group key agreement for ad hoc networks is proposed which arranges the group members in a cluster-based hierarchical spanning tree structure. The scheme uses Intra-cluster group key agreement (IC-GKA) to get the cluster key and arbitrary topology generalization of Diffie-Hellman (AT-GDH) to compute the final group key. BLS short signature algorithm (reducing the message size) is adopted to authenticate the messages exchanged during the protocol execution. The protocol can handle the dynamic membership changes in ad hoc networks. By security analysis of AT-GDH for the first time, the paper proves the semantic security of our proposed protocol. Complexity analysis shows that our protocol is suitable for ad hoc networks with large size.

A pairing-free identity-based authenticated group key agreement protocol for imbalanced mobile networks

The secure and reliable group communication gains popularity in imbalanced mobile networks due to the increase demand of the group-oriented applications such as teleconferences, collaborative workspaces, etc. For acquiring the group security objectives, many authenticated group key agreement (AGKA) protocols exploiting the public key infrastructure have been proposed, which require additional processing and storage space for validation of the public keys and the certificates. In addition, the most of the AGKA protocols are implemented using bilinear pairing and a map-to-point (MTP) hash function. The relative computation cost of the bilinear pairing is approximately two to three times more than the elliptic curve point multiplication (ECPM) and the MTP function has higher computation cost than an ECPM. Due to the limitation of communication bandwidth, computation ability, and storage space of the low-power mobile devices, these protocols are not suitable especially for insecure imbalanced mobile networks. To cope with the aforementioned problems, in this paper, we proposed a pairing-free identity-based authenticated group key agreement protocol using elliptic curve cryptosystem. It is found that the proposed protocol, compared with the related protocols, not only improves the computational efficiencies, but also enhances the security features.

Group Key Agreement From Signcryption

There is an intuitive connection between signcryption and key agreement. Such a connector may lead to a novel way to construct authenticated and efficient group key agreement protocols. In this paper, we present a primary approach for constructing an authenticated group key agreement protocol from signcryption. This approach introduces desired properties to group key agreement. What this means is that the signcryption gives assurance to a sender that the key is available only to the recipient, and assurance to the recipient that the key indeed comes from the sender. Following the generic construction, we instantiate a distributed two-round group key agreement protocol based on signcryption scheme given by Dent [8]. We also show that this concrete protocol is secure in the outsider unforgeability notion and the outsider confidentiality notion assuming hardness of the Gap Diffie-Hellman problem.

An ID-based authenticated dynamic group key agreement with optimal round

Group key agreement protocols are crucial for achieving secure group communications. They are designed to provide a set of users with a shared secret key to achieve cryptographic goal over a public network. When group membership changes, the session key should be refreshed efficiently and securely. Most previous group key agreement protocols need at least two rounds to establish or refresh session keys. In this paper, a dynamic authenticated group key agreement (DAGKA) protocol based on identity-based cryptography is presented. By making use of the members’ values stored in previous sessions, our Join and Leave algorithms reduce the computation and communication costs of members. In the proposed protocol, Setup and Join algorithms need one round. The session key can be refreshed without message exchange among remaining users in Leave algorithm, which makes the protocol more practical. Its security is proved under decisional bilinear Diffie-Hellman (DBDH) assumption in random oracle model.

A secure mobile virtual network computing environment for agent handshake

In this paper, we proposed a secure mobile virtual computing environment for agent handshake. In mobile virtual computing environment, agent handshake often appears in mobile virtual computing, we conclude that problem into a basic secure problem. In this paper, we propose an ID-based one round authenticated group key agreement protocol with bilinear pairings for solving agent handshake problem in mobile virtual computing environment, where all agents can generate the group session key in one round. Based on the intractability of elliptic curve discrete logarithm problem, we make sure every agent’s computing environment secure. We give a comprehensive security analysis on the proposed mobile virtual computing environment. Finally, we present the efficiency analysis about the proposed mobile virtual computing environment and other schemes, the proposed schemes require lower computation cost.

A novel authenticated group key agreement protocol for mobile environment

An authenticated group key agreement protocol allows a group of parties to authenticate each other and then determine a group key via an insecure network environment. In 2009, Lee et al. first adopted bilinear pairings to propose a new nonauthenticated group key agreement protocol and then extend it to an authenticated group key agreement protocol. This paper points out that the authenticated protocol of Lee et al. is vulnerable to an impersonation attack such that any adversary can masquerade as a legal node to determine a group key with the other legal nodes and the powerful node. This paper shall employ the short signature scheme of Zhang et al. to propose a new authenticated group key agreement protocol. The short signature scheme of Zhang et al. is proven to be secure against the adaptive chosen-message attacks in the random oracle model, so the proposed protocol can withstand the possible attacks. Besides, compared with the authenticated protocol of Lee et al., the proposed protocol is more secure and efficient.

Cryptanalysis of Lee et al.’s authenticated group key agreement

Authenticated key agreement protocols are to authenticate the users who will start a conversation and establish a common session key. In 2009, Cheng-chi Lee et al. proposed a new authenticated group key agreement based on a novel bilinear pairing to provide integrity of the transmitted messages. In this paper, we show that Cheng-chi Lee et al.’s protocol can only ensure the validity between the second step and the third step, and the intermediate message between the first step and the second step can be disturbed by attackers. That is, Cheng-chi Lee et al.’s protocol doesn’t achieve their goal.

Dynamic asymmetric group key agreement for ad hoc networks

A group key agreement protocol allows a set of users to establish a common symmetric key via open networks. Dynamic asymmetric group key agreement means that a dynamic set of users form a temporary group and negotiate to share a public encryption key, so that anyone can send message securely and efficiently to the temporary group. Users can join or leave the group efficiently without triggering a completely new key agreement protocol, which will greatly benefit the users in ad hoc networks. We describe a generic construction of dynamic asymmetric group key agreement by combining a conventional authenticated group key agreement, a public key encryption and a multi-signature. Then we give out an instance with constant rounds of interactions and constant transmission cost for each participant.

Analysis and improvement of a new authenticated group key agreement in a mobile environment

In 2009, Lee et al. (Ann Telecommun 64:735–744, 2009) proposed a new authenticated group key agreement protocol for imbalanced wireless networks. Their protocol based on bilinear pairing was proven the security under computational Diffie–Hellman assumption. It remedies the security weakness of Tseng’s nonauthenticated protocol that cannot ensure the validity of the transmitted messages. In this paper, the authors will show that Lee et al.’s authenticated protocol also is insecure. An adversary can impersonate any mobile users to cheat the powerful node. Furthermore, the authors propose an improvement of Lee et al.’s protocol and prove its security in the Manulis et al.’s model. The new protocol can provide mutual authentication and resist ephemeral key compromise attack via binding user’s static private key and ephemeral key.

Another Security Weakness in an Authenticated Group Key Agreement

Recently, Hwang et al. [1] showed that the authenticated group key agreement protocol proposed by Dutta and Barua [2] suffers from an impersonation attack and proposed an improvement to fix the problem. The goal of this paper is to prove that both the scheme of [2] and its improved version have another security weakness. In [2], it is claimed that the protocol has the ability to detect the presence of a corrupted group member so that if an invalid message is sent, then this can be detected by all legitimate members of the group. In this paper, we show that this claim is not true even in the improved version. We prove that two malicious participants can prohibit legitimate participants from obtaining the same shared key and remain completely unnoticed.

ID-based authenticated group key agreement from bilinear maps

Authenticated group key agreement (GKA) is an important cryptographic mechanism underlying many collaborative and distributed applications. Recently, identity (ID)-based authenticated GKA has been increasingly researched because of the authentication and simplicity of the ID-based cryptosystem. However, there are two disadvantages with this kind of mechanism: 1) the private key escrow is inherent and 2) the Private Key Generator (PKG) must send client private keys over secure channels, making private key’s distribution difficult. The two disadvantages, particularly secure channels, may be unacceptable for secure group communications application. Fortunately, we can avoid both of them. In this paper, with bilinear maps on ECC, we present a new authenticated group key agreement protocol that does not require secure channels. The basic idea is the usual way of circumventing escrow: double key and double encryption (verification). The secret key of a user is generated by a key generation center (KGC) and the user collaboratively. Each of them has “half” of the secret information about the secret key of the user, and there is no secret key distribution problem. In addition, the computation cost of the protocol is very low because the main computation is binary addition.

A new authenticated group key agreement in a mobile environment

A group key agreement protocol enables a group of communicating parties over an untrusted, open network to come up with a common secret key. It is designed to achieve secure group communication, which is an important research issue for mobile communication. In 2007, Tseng proposed a new group key agreement protocol to achieve secure group communication for a mobile environment. Its security is based on the decisional Diffie–Hellman assumption. It remedies the security weakness of the protocol of Nam et al. in which participants cannot confirm that their contributions were actually involved in the group key. Unfortunately, Tseng’s protocol is a nonauthenticated protocol that cannot ensure the validity of the transmitted messages. In this paper, the authors shall propose a new authenticated group key agreement to remedy it. It is based on bilinear pairings. We shall prove the security of the proposed protocol under the bilinear computational Diffie–Hellman assumption. It is also proven to a contributory group key agreement protocol.

Comments on an ID-Based Authenticated Group Key Agreement Protocol with Withstanding Insider Attacks

In PKC 2004, Choi et al. proposed an ID-based authenticated group key agreement (AGKA) protocol using bilinear pairings. Unfortunately, their protocol suffered from an impersonation attack and an insider colluding attack. In 2008, Choi et al. presented an improvement to resist insider attacks. In their modified protocol, they used an ID-based signature scheme on transcripts for binding them in a session to prevent replay of transcripts. In particular, they smartly used the batch verification technique to reduce the computational cost. In this paper, we first show that Choi et al.'s modified AGKA protocol still suffers from an insider colluding attack. Then, we prove that the batch verification of the adopted ID-based signature scheme in their modified protocol suffers from a forgery attack.

Efficient and provably secure password-based group key agreement protocol

This paper considers the issue on authenticated group key agreement protocol among n users broadcasting communication over an insecure public network. Many authenticated group Diffie-Hellman key agreement protocols have been proposed to meet the challenges. However, existing protocols are either limited by the use of public key infrastructure or by their scalability, requiring O(n) rounds. To overcome these disadvantages, we propose an efficient password-based group key agreement protocol resistant to the dictionary attacks by adding password-authentication services to a non-authenticated multi-party key agreement protocol proposed by Horng. The proposed protocol is very efficient since it only requires constant rounds to agree upon a session key, and each user broadcasts a constant number of messages and only requires four exponentiations. Under the Decisional Diffie-Hellman assumption, we will show the proposed protocol is provably secure in both the ideal-cipher model and the random-oracle model.

Secure authenticated group key agreement protocol in the MANET environment

Due to dynamic and infrastructure-less nature of Mobile Ad hoc Network (MANET) environment, there exist number of threats as mobile devices and nodes could freely move around in MANET such as eavesdropping of communications channels, modification of sensitive m-commerce transactions, Denial of Service(DoS), vulnerabilities of impersonation by malicious insiders etc. In this paper, we propose a novel authenticated group key agreement protocol for end-to-end security in the MANET environment without any infrastructure that is based on Burmester and Desmedt group key agreement protocol (Burmester M, Desmedt Y. A secure and efficient conference key distribution system. Advances in Cryptology – EuroCrypt ’94, Lecture Notes in Computer Science 1995;950:275–86) and their variants (Choi KY, Hwang JY, Lee DH. Efficient ID-based group key agreement with bilinear maps. Public Key Cryptography – PKC, Lecture Notes in Computer 2004;2947:130–144)]. We also design practical enhancements of BD and Choi et al.'s protocols that not only detect, but also identify malicious insiders by using the trusted arbiter who only involves in the protocol if the cheating has been occurred.

Security weakness in an authenticated group key agreement protocol in two rounds

Dutta and Barua recently proposed an efficient authenticated group key agreement protocol for dynamic membership. To reduce computation overhead, the protocol makes use of a simplified authentication mechanism such that only two neighbors of a participant check if a message is originated from the participant. In this paper, we show that the authenticated group key agreement protocol has some security breaches caused by the restrictive authentication. In addition, we present a simple method to fix the security breaches and prove its security under the standard assumptions.

ID-Based Authenticated Group Key Agreement Secure against Insider Attacks

In 2004, Choi et al. proposed an ID-based authenticated group key agreement. Unfortunately, their protocol was found to be vulnerable to the insider attacks by Zhang, Chen and Shim. To prevent insider attacks, Shim presented a modification of Choi et al.'s protocol. In this letter, we first show that Shim's modification is still insecure against insider attacks. We then present a modification of Choi et al.'s protocol that resists insider attacks. The counter-measure uses an ID-based signature on transcripts in order to bind them in a session. This prevents any replay of transcripts. Especially, by applying ID-based batch verification, the proposed one still consists of two rounds and is computationally efficient.

그룹 사용자간 안전한 콘텐츠 전송을 위한 Zhou의 ID-기반의 인증된 그룹 키 교환 프로토콜 분석

유료 콘텐츠를 정당한 서비스 수신자에게 안전하게 제공하기 위해서는 서비스 제공자와 수신자 사이에 안전한 키 교환이 필요하다. 그룹 키 교환 프로토콜은 이러한 그룹에 속한 멤버들이 공개된 통신망을 이용하여 안전하고 효율적인 방법으로 그룹의 세션키를 설정할 수 있게 한다. 최근에 L. Zhou는 효율적인 인증된 그룹 키 교환 프로토콜을 설계하였다. 본 논문에서 우리는 Zhou의 기법이 전방향 안전성을 제공하지 않음을 보인다. An authenticated group key agreement protocol allows a group of parties communicating over an insecure network to share a common secret key. In this paper, we show that Zhou et al.'s ID-based authenticated group key agreement schemes do not provide forward secrecy.

Authenticated Group Key Agreement Protocols for Ad hoc Wireless Networks

The lack of fixed infrastructure, both physical and organizational, and the highly dynamic nature of ad hoc networks, presents a major challenge in providing secure, authenticated communication for these networks. Traditional key management solutions reported in the literature lack both the flexibility and robustness required to cope with the dynamic nature of ad hoc networks. In this paper, we propose two different n-party authenticated key agreement protocols enabling authorized nodes to generate their own session keys. The first protocol introduces a solution based on clustering techniques suitable for networks with partial structure and composed of a large number of nodes. The second protocol assumes no structure and provides authentication with a minimal increase in communication and computational overhead required.

Further Analysis of ID-Based Authenticated Group Key Agreement Protocol from Bilinear Maps

Recently, Choi et al. proposed an ID-based authenticated group key agreement with bilinear maps. Subsequently, Zhang and Chen showed that the protocol does not provide authenticity as claimed by replaying transcripts of the past session. To prevent those replay attacks, they suggest adding a time parameter to the message being signed. However, despite of such a modification, we show that the protocol is still insecure against insider colluding attacks without replaying transcripts of the past session.