A Novel Fuzzy Identity-Based Signature with Dynamic Threshold

The fuzzy identity-based signature allows a user with the private key for identity W to verify a signature signed by identity S if and only if W and S are within a certain distance judged by a threshold t. In previous fuzzy identity-based signature schemes, the threshold t is static and cannot be changed according to dynamic environment. This paper proposes a novel FISAT scheme(fuzzy identity-based signature with dynamic threshold), which is based on the bilinear maps and multi-sequence of Diffie-Hellman exponents assumption. The threshold in FISAT can be dynamically selected according to the importance of the message. Furthermore, FISAT only uses constant keys and ciphertext, which improves transmission performance.