%T Dynamic Universal Accumulators for DDH Groups and Their Application to Attribute-Based Anonymous Credential Systems
%A Man Ho Au
%A Patrick P. Tsang
%A Willy Susilo
%A Yi Mu
%R Technical Report TR2009-643
%I Dartmouth College, Computer Science
%C Hanover, NH
%D April 2009
%U http://www.cs.dartmouth.edu/reports/TR2009-643.pdf
%X
 We present the first dynamic universal accumulator that allows (1) the
 accumulation of elements in a DDH-hard group G and (2) one who
 knows x such that y=g^x has --- or has not --- been
 accumulated, where g generates G, to efficiently prove her
 knowledge of such x in zero knowledge, and hence without revealing,
 e.g., x or y.
   We introduce the Attribute-Based Anonymous Credential
 System (ABACS), which allows the verifier to authenticate anonymous
 users according to any access control policy expressible as a
 formula of possibly negated boolean user attributes. We
 construct the system from our accumulator.
%Z
 This report is the extended version of the paper to appear in CT-RSA '09 under the same title.