Authors:
María Isabel González Vasco
1
;
Somayeh Heidarvand
2
and
Jorge L. Villar
2
Affiliations:
1
Univ. Rey Juan Carlos, Spain
;
2
Univ. Politécnica de Cataluña, Spain
Keyword(s):
Anonymous authentication, Blind signatures, Clone detection, Traceability.
Related
Ontology
Subjects/Areas/Topics:
Cryptographic Techniques and Key Management
;
Data and Application Security and Privacy
;
Information and Systems Security
;
Privacy
;
Public Key Crypto Applications
;
Security and Privacy Policies
Abstract:
In traditional e-cash systems, the tradeoff between anonymity and fraud-detection is solved by hiding the identity of the user into the e-coin, and providing an additional triggering mechanism that opens this identity in case of double spending. Hence, fraud detection implies loss of anonymity. This seems to be a somewhat natural solution when universality of the e-coin is required (i.e., the use of the coin is not determined at the time the coin is generated). However, much simpler protocols may suffice if we only want to prevent that payments for accessing certain services are over-used, even when users’ anonymity is perfectly preserved.
In this paper we propose a simple and efficient Subscription Scheme, allowing a set of users to anonymously pay for and request access to different services offered by a number of service providers. In our approach, the use of the token is completely determined at issuing time, yet this final aim remains hidden to the issuing authority. Moreover,
fraud detection here implies no loss of anonymity; as we make access tokens independent of the owner in a quite simple and efficient way. On the other hand, if different usages of the same token are allowed, these are fully traceable by the service providers.
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