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Giuseppe Ateniese, Michael Stiener and Gene Tsudik Presented by Young Hee Park November 11, 2005. Authenticated Group Key Agreement and Friends. 1. Outline. Introduction Authenticated 2-party Key Agreement Proposed Schemes Authenticated Group Key Agreement A-GDH protocol
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Giuseppe Ateniese, Michael Stiener and Gene Tsudik Presented by Young Hee Park November 11, 2005 Authenticated Group Key Agreement and Friends 1
Outline • Introduction • Authenticated 2-party Key Agreement • Proposed Schemes • Authenticated Group Key Agreement • A-GDH protocol • Complete Group Key Authentication • SA-GDH protocol • Conclusions • Future Work
Introduction • Secure and efficient communications among group members in dynamic peer groups • Group key establishment
Introduction • Authenticated key agreement in dynamic peer groups • Extend 2-party authenticated key agreement to group Diffie-Hellman key agreement • Security services • Perfect forward secrecy (PFS) • Resistance to known-key attacks • Key authentication • Key confirmation and key integrity
M1 M2 Authenticated 2-party Key Agreement • 2-partyDiffie-Hellman key agreement M1M2 • Authenticated 2-party key agreement
Authenticated Group Key Agreement • Overview of GDH.2 M1 M2 M3 M4
Authenticated Group Key Agreement • A-GDH.2 M1 M2 M3 M4
Authenticated Group Key Agreement • Provides perfect forward secrecy • Resistant to passive known key attacks • Weak form of key authentication • Key is not directly authenticated between arbitrary nodes • All key authentication is performed through Mn • No one can be sure of other members’ participation Complete group key authentication
Complete Group Key Agreement(SA-GDH.2) M3 M1 M2 M4
Complete Group Key Agreement • SA-GDH.2 • Advantages • Perfect forward secrecy • Resistance to know-key attacks • Complete key authentication • Each member can be aware of the exact membership • Disadvantages • More expensive than A-GDH.2 • Every member Mi requires n exponentiations • Every member Mi requires many pairwise keys(Kij)
Conclusions • Secure authenticated key agreement protocol for dynamic peer groups • Extend 2-party authenticated key agreement to n parties authenticated key agreement • Provides perfect forward secrecy • Key authentication, key confirmation and integrity • Resistance to active attacks
Future Work • Develop a general-purpose toolkit for key agreement and related security services in dynamic peer groups • Develop more efficient secure group key agreement protocol which provides the resistance to insider attacks and more group security services