Anonymous Counting Tokens

In this paper we introduce a new primitive called anonymous counting tokens (ACTs) which effectively allow clients to obtain blind signatures on messages of their choice, and in addition allow enforcing rate limiting on the number of tokens that a client can obtain for each message. In particular, we enforce that each client will be able to obtain only one token per message. We enable this new property while maintaining the unforgeability and unlinkability properties required for anonymous token schemes. We present three ACT constructions which are based on different hardness assumptions including q-DHI in the RO model, SXDH in bilinear groups with or without RO, and finally the generic bilinear group model. We estimate the efficiency costs that each construction offers.

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