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Technical Report

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Technical Report Number



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.


This report is the extended version of the paper to appear in CT-RSA '09 under the same title.