A Strongly Unlinkable Group Signature Scheme with Matching-Based Verifier-Local Revocation for Privacy-Enhancing Crowdsensing

A group signature scheme allows us to anonymously sign a message on behalf of group. One important issues in the signatures is user revocation, and thus lots revocable (RGS) schemes have been proposed so far. applications suitable privacy-enhancing crowdsensing, where mobile sensing users be authenticated hide location. In environment, verifier-local revocation (VLR) type RGS are suitable, since list (RL) not needed side. However, conventional VLR-RGS schemes, check verifier needs O(R) cryptographic operations for number R revoked users. On this background, with efficient recently proposed, just (bit-string) matching. existing linkable same interval or application-independent task public index. The linkability useful some scenarios, but want unlinkability stronger anonymity. paper, by introducing property that at most K unlinkable can issued signer during each fixed integer K, we propose token our scheme, even unlinkable. Furthermore, used indexes hidden, strong anonymity remains. overheads computational costs algorithm RL size. We show practical use cases crowdsensing.