[HGI-News] HGI-Seminar am Montag, 05.07.2004

[hgi-news at lists.ruhr-uni-bochum.de]

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		  	       Mark Manulis
		Lehrstuhl für Netz- und Datensicherheit
			Ruhr-Universität Bochum	 
            	  
       "Pseudonym Generation Scheme for Ad-Hoc Group Communication"


               Montag, 05.07.2004, 13:15 Uhr, IC 4/39,


Abstract

In this presentation we describe the advantages of using iterative
Diffie-Hellman (IDH) key trees for mobile ad-hoc group communication
scenarios. We focus  on the Tree-based Group Diffie-Hellman (TGDH) protocol
suite that consists of group key agreement protocols based on IDH key trees.
Furthermore, we consider  the anonymity of members during group
communication over a public broadcast channel that provides untraceability
of messages. The main goal of the proposed  pseudonym generation scheme is
to allow group members to generate their own pseudonyms that can be linked
to their real identities only by a democratic  decision of some interacting
group members. The real identities are bound to public keys used in the
group key agreement. The pseudonym generation scheme is  an add-on to the
TGDH protocol suite.

Motivation:
Different appliance scenarios can be considered for the ad-hoc group
communication with pseudonyms, e.g. members of directing board of a company
might want  to communicate securely and anonymously, without having to trust
a third party. If at least one of the group members breaches the
communication rules by  broadcasting some misleading information, then other
members might want to reveal her identity. The decision whether such dispute
case has been occured is  democratic since none of group members is obliged
to take part in the revealing process. This is the main difference to
communication scenarios with a  designated group manager that decides when a
dispute case has occured. To achieve such democratic decision, our scheme
supports (k, n)-threshold revocation  method with k being a power of 2.
Another example is a spontaneously organized auction by members with mobile
devices that bid using hidden identities. After  the auction is finished the
identity of the winner should be revealed to the group. In this scenario
members are interested in providing a correct data while  generating
pseudonyms, otherwise a winner would not be able to prove the possession of
his pseudonym.

 

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VORTRÄGE IM SS 2004:
(Abstracts sind hier:
 http://www.crypto.ruhr-uni-bochum.de/ge/seminar/hgi_sose04.html)

 
 19.04.2004, Marc Stevens, ITSC - RUB, 13.00 c.t. IC 4/39,,
 "Arithmetic on Hyperelliptic curves of genus 1 and 2"

 26.04.2004, Jonathan Hammell, COSY - RUB, 13.00 c.t. IC 4/39,
 "Recognition in a Low-Power Environment"

 03.05.2004, Kai Schramm, COSY - RUB, 13.00 c.t. IC 4/39,
 "Internal Collisions in AES"

 17.05 Christian Tobias, JLU Gießen, 13.15 hrs. IC 4/39,
 "Design und Analyse kryptografischer Bausteine auf nicht-abelschen
Gruppen"

 24.05 Jamshid Shokrollahi, Uni Paderborn, 13.15 hrs. IC 4/39,
 "Unifying structures for polynomial and normal bases"

 31.05 no seminar (Holiday: Pfingsmontag)

 7.06 Lars Pontow, COSY Group -RUB, 13:15 hrs. IC 4/39,
 "Elliptic Curve Cryptography as a Case Study for Hardware/Software
Codesign"

 14.06 Kerstin Lemke, COSY Group -RUB, 13.15 hrs. IC 4/39,
 "DPA on n-bit sized Boolean and Arithmetic Operations and its   application
to IDEA, RC6 and the HMAC-Construction"

 16.06 Eike Kiltz, Lehrstuhl Mathematik und Informatik -RUB, 13:30 hrs. NA
1/58 (Friedrich-Sommer Raum)
"Secure Constant Round Multi-Party Computation for Equality, Comparison and
Bits"

 21.06 Howon Kim (ETRI-Korea), COSY Group -RUB, 13.15 hrs. IC 4/39,
"Hyperelliptic Curve Coprocessors on FPGA"

 28.06 Werner Schindler, BSI, 13:15 hrs, IC 4/39 	
"Über die Modellierung und Analyse physikalischer  Zufallszahlengeneratoren"

 5.07 Mark Manulis, NDS Group -RUB, 13:15 hrs. IC 4/39,
 "Pseudonym Generation Scheme for Ad-Hoc Group Communication"

 12.07 TBA

 19.07 TBA

 26.07 TBA



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M.Tech. Sandeep Kumar
Chair for Communication Security
Dept. of Electr. Eng. & Information Sciences
Ruhr-University Bochum
44780 Bochum, Germany

URL: www.crypto.rub.de