A Robust Authenticated Key Agreement Protocol.

H.B. Tang, Liu Xin-song

Yuh‐Min Tseng

By its very nature, a non-authenticated multi-party key agreement protocol cannot provide participant and message authentication, so it must rely on an authenticated network channel. This paper presents the inability of two famous multi-party key agreement protocols to withstand malicious participant attacks, even though their protocols are based on the authenticated network channel. This attack involves a malicious participant disrupting the multi-party key agreement among honest participants. In this case, other honest participants do not correctly agree on a common key. Obviously, the malicious participant cannot obtain the common key either, and the communication confidentiality among participants is not breached. However, in some emergency situations or applications, a multi-party key agreement protocol design that is resistant to malicious participants is useful. Therefore, in this paper, a non-authenticated multi-party key agreement protocol resistant to malicious participants is proposed. The proposed robust protocol requires constant rounds to establish a common key. Each participant broadcasts a constant number of messages. Under the assumption of the Decision Diffie–Hellman problem and the random oracle model, we will show that the proposed protocol is provably secure against passive adversaries and malicious participants.

Kee-Won Kim, Eun‐Kyung Ryu, Hyung-Mok Lee +1 more

Massoud, Hadian, Dehkordi +2 more

Yimin Guo, Guo Ya-jun

Anonymity, robust synchronization, and perfect forward secrecy are the most important security properties of authenticated key agreement (AKA) protocols. Designing AKA protocols that simultaneously achieve these security properties and availability in the IoT environment is a challenging task. AKA protocols built using public key cryptographic primitives have advantages in achieving these critical security properties, but performing expensive public-key cryptographic operations is inefficient for resource-constrained IoT devices. The authentication protocols based on symmetric cryptographic primitives are often subject to various attacks. This paper proposes a secure lightweight AKA protocol with critical security properties (called CS-LAKA) for IoT environments without using public-key cryptographic primitives. LAKA cleverly achieves the security goals of anonymity, robust synchronization, and perfect forward secrecy by embedding dynamic identities in authenticators, and a few additional exchange messages are added. This enables LAKA to have both robust security and high efficiency. Subsequently, we perform a formal security analysis to prove that LAKA is secure, and compared with existing related schemes, LAKA has obvious advantages in terms of security, functionality and running performance.

Gene Tsudik, Stanisław Jarecki, Jihye Kim

The last decade has witnessed a sharp spike in the popularity of group applications, such as multi-media conferencing, collaborative workspaces, as well as dynamic coalitions common in law enforcement and disaster rescue scenarios. Standard security services required in such group settings (such as confidentiality, integrity and authentication) can be efficiently achieved if all group members share a secret key. A group key agreement protocol (GKA) provide a technique for any set of participating players to collaboratively establish a shared key. In this thesis, we tackle two challenging issues in GKA: robustness and privacy-preserving authentication. Robustness improves performance by guaranteeing completion of GKA protocols despite participating player or communication failures. Affiliation-hiding authenticated GKA prevents from man-in-the-middle-attacks by authenticating players in a privacy-preserving manner. We propose a two-round group key agreement protocol, which offers a natural trade-off between message size and the desired level of fault-tolerance. We demonstrate that in a realistic setting of random player faults, the new protocol has logarithmic-sized messages and expected round complexity close to two. We generalize a robust group key agreement protocol to support heterogeneous players for a general environment. We prove the security of the proposed protocols under the standard cryptographic assumptions. We present the formal definition of the affiliation-hiding GKA in a standard PKI model with re-usable certificates. The model includes strong security properties, called perfect forward secrecy (PFS) and linkable affiliation-hiding (LAH)—that an key agreement protocol might provide in the face of player corruptions and session compromises. We construct two variants of optimal-cost AH-AGKA protocols, which satisfy PFS and LAH notions under the standard cryptographic assumptions in the random oracle model. The protocol yields minimal costs: three rounds of interaction matches the round complexity of non-private PFS authenticated GKA and its computation costs are comparable to the cost of unauthenticated GKA.