Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

The Computer Journal

Authenticated Tree-Based R-LWE Group Key Exchange

Hector B. Hougaard, Atsuko Miyaji

Published Sep 24, 2021• 2 citations
Publisher

Abstract

Abstract We present the first constant round, multicast, authenticated tree-based R-LWE group key exchange protocol with logarithmic communication and memory complexity. Our protocol achieves post-quantum security through a reduction to a Diffie–Hellman-like analogue to the decisional R-LWE problem. We also present a sequential version with constant memory complexity but a logarithmic number of rounds and communication complexity.

DOI
10.1093/comjnl/bxab165

Related papers

Constant Round Group Key Exchange with Logarithmic Computational Complexity.

Junghyun Nam, Youngsook Lee, Dongho Won

Protocols for group key exchange (GKE) are cryptographic algorithms that describe how a group of parties communicating over a public network can come up with a common secret key. Due to their critical role in building secure multicast channels, a number of GKE protocols have been proposed over the years in a variety of settings. However despite many impressive achievements, it still remains a challenging problem to design a secure GKE protocol which scales very well for large groups. Our observation is that all provably-secure constant-round GKE protocols providing forward secrecy thus far are not fully scalable, but have a computational complexity that scales only linearly in group size. Motivated by this observation, we propose a new GKE protocol that not only offers full scalability in all directions but also attains provable security against active adversaries. Full scalability is achieved by using a complete binary tree structure where users are arranged on both internal and leaf nodes. Security is proved via reduction to the decisional Diffie-Hellman assumption in a well-defined formal model of communication and adversarial capabilities.

•Jan 1, 2006•1 citation

Provably authenticated group Diffie-Hellman key exchange - The dynamic case (Extended abstract)

Emmanuel Bresson, Olivier Chevassut, David Pointcheval

Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange(AKE) are designed to work in scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In this paper, we define a security model for this problem and use it to precisely define Authenticated Key Exchange (AKE) with ''implicit'' authentication as the fundamental goal, and the entity-authentication goal as well. We then define in this model the execution of a protocol modified from a dynamic group Diffie-Hellman scheme offered in the literature and prove its security.

International Conference on the Theory and Application of Cryptology and Information Security•Sep 20, 2001•13 citations

Provably authenticated group Diffie-Hellman key exchange - The dynamic case (Extended abstract) - eScholarship

Emmanuel Bresson, Olivier Chevassut, David Pointcheval

Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange(AKE) are designed to work in scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In this paper, we define a security model for this problem and use it to precisely define Authenticated Key Exchange (AKE) with implicit authentication as the fundamental goal, and the entity-authentication goal as well. We then define in this model the execution of a protocol modified from a dynamic group Diffie-Hellman scheme offered in the literature and prove its security.

•Sep 20, 2001•1 citation

Diffie-Hellman Key Exchange Protocol Based on Ring-LWE

Zhimin Yu, Jing Zheng-Jun, Li Shi-Cun

In this paper, we first construct a one-round Diffie-Hellman key exchange protocol based on Ring-LWE.The security of our construction is based on the hardness of the Ring-LWE problem.Second, we adaptively extend our construction from Ring-LWE to LWE.Finally, we efficiently implement our key exchange protocols based on Ring-LWE and LWE.

The Open Cybernetics & Systemics Journal•Sep 10, 2015•1 citation

Provably authenticated group Diffie-Hellman key exchange - The dynamic \ncase (Extended abstract)

Emmanuel Bresson, Olivier Chevassut, David Pointcheval

Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange(AKE) are designed to work in scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In this paper, we define a security model for this problem and use it to precisely define Authenticated Key Exchange (AKE) with "implicit" authentication as the fundamental goal, and the entity-authentication goal as well. We then define in this model the execution of a protocol modified from a dynamic group Diffie-Hellman scheme offered in the literature and prove its security.

•Sep 20, 2001•1 citation

Design and Implementation of Constant-Round Dynamic Group Key Exchange from RLWE

Rakyong Choi, Dongyeon Hong, Seongho Han +3 more

Group Key Exchange (GKE) is required for secure group communication with high confidentiality. In particular, a trusted authority can handle issues that happen by the malicious actions of group members, but it is expensive to deploy and not suitable in a dynamic setting where the network requires frequent membership status changes. To overcome these issues, we designed yet another quantum-resistant constant-round GKE based on lattice without a trusted authority based on Apon et al.'s protocol (PQCrypto 2019) by modifying their key computation phase. Then, we describe the novel dynamic authenticated GKE (called DRAG) with membership addition/deletion procedures in Ring Learning with Errors (RLWE) setting, while the former ones are built from Diffie-Hellman problem. Under the specific adversary who can leak the long-term secret key from the party, we suggest a rigorous proof of DRAG in the random oracle model based on the hardness assumption of RLWE problem and the property of Rényi divergence. As a proof of concept, implementation details are described to meet level 1 NIST security. Our implementation is reasonable for practical use since the total runtime to get a group secret key takes about 3 msec and it can be considered as a reference implementation of other quantum-resistant GKEs.

IEEE Access•Jan 1, 2020•14 citations
Abstract We present the first constant round, multicast, authenticated tree-based R-LWE group key exchange protocol with logarithmic communication and memory complexity. Our protocol achieves post-quantum security through a reduction to a Diffie–Hellman-like analogue to the decisional R-LWE problem. We also present a sequential version with constant memory complexity but a logarithmic number of rounds and communication complexity.
Protocols for group key exchange (GKE) are cryptographic algorithms that describe how a group of parties communicating over a public network can come up with a common secret key. Due to their critical role in building secure multicast channels, a number of GKE protocols have been proposed over the years in a variety of settings. However despite many impressive achievements, it still remains a challenging problem to design a secure GKE protocol which scales very well for large groups. Our observation is that all provably-secure constant-round GKE protocols providing forward secrecy thus far are not fully scalable, but have a computational complexity that scales only linearly in group size. Motivated by this observation, we propose a new GKE protocol that not only offers full scalability in all directions but also attains provable security against active adversaries. Full scalability is achieved by using a complete binary tree structure where users are arranged on both internal and leaf nodes. Security is proved via reduction to the decisional Diffie-Hellman assumption in a well-defined formal model of communication and adversarial capabilities.
Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange(AKE) are designed to work in scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In this paper, we define a security model for this problem and use it to precisely define Authenticated Key Exchange (AKE) with ''implicit'' authentication as the fundamental goal, and the entity-authentication goal as well. We then define in this model the execution of a protocol modified from a dynamic group Diffie-Hellman scheme offered in the literature and prove its security.
Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange(AKE) are designed to work in scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In this paper, we define a security model for this problem and use it to precisely define Authenticated Key Exchange (AKE) with implicit authentication as the fundamental goal, and the entity-authentication goal as well. We then define in this model the execution of a protocol modified from a dynamic group Diffie-Hellman scheme offered in the literature and prove its security.
Dynamic group Diffie-Hellman protocols for Authenticated Key Exchange(AKE) are designed to work in scenario in which the group membership is not known in advance but where parties may join and may also leave the multicast group at any given time. While several schemes have been proposed to deal with this scenario no formal treatment for this cryptographic problem has ever been suggested. In this paper, we define a security model for this problem and use it to precisely define Authenticated Key Exchange (AKE) with "implicit" authentication as the fundamental goal, and the entity-authentication goal as well. We then define in this model the execution of a protocol modified from a dynamic group Diffie-Hellman scheme offered in the literature and prove its security.
Group Key Exchange (GKE) is required for secure group communication with high confidentiality. In particular, a trusted authority can handle issues that happen by the malicious actions of group members, but it is expensive to deploy and not suitable in a dynamic setting where the network requires frequent membership status changes. To overcome these issues, we designed yet another quantum-resistant constant-round GKE based on lattice without a trusted authority based on Apon et al.'s protocol (PQCrypto 2019) by modifying their key computation phase. Then, we describe the novel dynamic authenticated GKE (called DRAG) with membership addition/deletion procedures in Ring Learning with Errors (RLWE) setting, while the former ones are built from Diffie-Hellman problem. Under the specific adversary who can leak the long-term secret key from the party, we suggest a rigorous proof of DRAG in the random oracle model based on the hardness assumption of RLWE problem and the property of Rényi divergence. As a proof of concept, implementation details are described to meet level 1 NIST security. Our implementation is reasonable for practical use since the total runtime to get a group secret key takes about 3 msec and it can be considered as a reference implementation of other quantum-resistant GKEs.