Double-trapdoor anonymous tags for traceable signatures

摘要

This paper introduces a novel tool, public-key anonymous tag system, which is useful in building controlled privacy-protecting protocols. The double-trapdoor structure of the system not only allows the authority to create a token which can trace someone’s tags without violating anonymity of the tag issuer, but also allows the issuer to claim or deny the authorship of a tag in the stateless manner. An efficient instantiation based on simple assumptions in the standard model is presented. We then use it for a modular construction of traceable signatures. Our scheme supports a signature authorship claiming (and denial) that binds a claim to the public-key of the signer unlike that in known schemes. It is also the first scheme in the literature which features concurrent joining of users, stronger anonymity, and so on without random oracles.