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LING-LING XU AND FANG-GUO ZHANG+
School of Information Science and Technology
Sun Yat-sen University
Guangzhou, 510275 P.R. China
In this paper, we introduce the concept of oblivious transfer with threshold access
control. Namely, for each message in a database, the server associates an attribute set £n
with it such that the message can only be available, on request, to the users who possess
at least t attributes out of £n. Meanwhile, after the server and users execute the protocol,
the server will not learn anything about the identities, attributes or message choices of
the users. The essential idea of ¡§threshold¡¨ access control is to define the minimum
number of attributes from a given set of attributes that users have to possess in order to
obtain the message. Combining Sahai and Waters¡¦ fuzzy identity-based encryption with
a credential signature scheme, we present a concrete construction for the oblivious transfer
with threshold access control which is proved secure in the standard model.
Received May 27, 2010; revised August 27 & September 23, 2010; accepted October 6, 2010.
Communicated by Tzong-Chen Wu.
* This paper was supported by the National Natural Science Foundation of China (Nos. 60773202, 61070168)
and 973 Program (No. 2006CB303104).
+ Corresponding author.