Authors:
Keita Emura
1
and
Takashi Sato
2
Affiliations:
1
National Institute of Information and Communications Technology (NICT), Japan
;
2
Japan Advanced Institute of Science and Technology (JAIST), Japan
Keyword(s):
Group Key Exchange, On-demand Computation of Subgroup Keys.
Related
Ontology
Subjects/Areas/Topics:
Applied Cryptography
;
Authentication
;
Cryptographic Techniques and Key Management
;
Data Engineering
;
Databases and Data Security
;
Information and Systems Security
;
Obstacles
;
Security in Distributed Systems
;
Security Protocols
;
Sensor Networks
Abstract:
In AFRICACRYPT2010, Abdalla, Chevalier, Manulis, and Pointcheval proposed an improvement of group key exchange (GKE), denoted by GKE+S, which enables on-demand derivation of independent secret subgroup key for all potential subsets. On-demand derivation is efficient (actually, it requires only one round) compared with GKE for subgroup (which requires two or more rounds, usually) by re-using values which was used for the initial GKE session for superior group. In this paper, we improve the Abdalla et al. GKE+S protocol to support key randomization. In our GKE+S protocol, the subgroup key derivation algorithm is probabilistic, whereas it is deterministic in the original Abdalla et al. GKE+S protocol. All subgroup member
can compute the new subgroup key (e.g., for countermeasure of subgroup key leakage) with just one-round additional complexity. Our subgroup key establishment methodology is inspired by the “essential idea” of the NAXOS technique. Our GKE+S protocol is authenticated key
exchange (AKE) secure under the Gap Diffie-Hellman assumption in the random oracle model.
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