A Fuzzy Identity Based Signature Scheme

In this paper, we introduce a new type of identity based signature (IBS) scheme that we call fuzzy identity based signature (FIBS). In a FIBS scheme, user´s identity are viewed as set of descriptive attributes. A user can use attributes omega to verify a signature signed with the attributes omega´ if and only if omega and omega´ are within a certain distance of each other as judged by some metric. We present a FIBS scheme from bilinear pairings. The proposed FIBS scheme is both error-tolerant and secure against collusion attacks. We also prove that the proposed FIBS scheme is existentially unforgeable under a chosen message attack and selective fuzzy identity attack in the random oracle model, given that the (k + 1)-EP problem (where k = 2) is hard.