[HGI-News] HGI Seminar Do.17.Jan: Privacy-Protecting Multi-Coupon Scheme (A. Escalante)

[Newsletter des Horst Görtz Instituts]

Hallo,

im Rahmen des HGI-Seminars "Aktuelle Themen der IT-Sicherheit" wird  
am kommenden Donnerstag der folgende Vortrag angeboten:

Alberto Escalante (Lehrstuhl für Systemsicherheit, Ruhr Univ. Bochum)
*"A Privacy-Protecting Multi-Coupon Scheme with Stronger Protection against 
Splitting"
*
Donnerstag, den 17. Januar um  11.00 Uhr
Raum: IC 4/161.

Alle Interessierte sind herzlich eingeladen!


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Zusammenfassung:

A multi-coupon represents a collection of k coupons that a customer can buy from a vendor, and later redeem to him in exchange for certain goods or services, such as discounts or prepaid items. Recently, Nguyen (FC 2006) introduced an unforgeable privacy-protecting multi-coupon system with constant complexity for issuing and redemption of multi-coupons. In his scheme, sharing of coupons is discouraged through a property called weak unsplittability, where sharing of a single coupon implies sharing of the whole multi-coupon (all-or-nothing sharing). Previous schemes still lack some features required for many applications in practice, and also stronger forms of unsplittability are desirable. In this talk, we present the basic principles of multi-coupon schemes. Then, we introduce a new security model with stronger definitions, and finally, we describe a concrete realization, where single coupons within a multi-coupon may represent different goods or services, have independent validity periods, and must be redeemed sequentially ensuring a stronger version of unsplittability compared to all-or-nothing sharing. The complexity of the proposed scheme is linear in k for the generation of multi-coupons and constant for each redeemed single coupon. 

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Informationen über die nächsten geplannten Vorträge im Rahmen des
HGI-Seminars sind auch im Web zu finden:
http://www.hgi.rub.de/deutsch/lehrangebot/seminar/ws200708.html

Gruß,
Biljana Cubaleska