Using a biometric as an identity has the advantage that identities are unique if the underlying biometric is of a good quality, such as fingerprints, faces, irises, etc. However, biometric measurements are noisy and the existing identity-based systems cannot be used directly to construct this scheme. The error-tolerance property(Fuzzy) can be used to solve this problem. Based on the error-tolerance property, a new biometric identity based signature scheme is proposed. Our scheme is constructed in the standard model and achieves a strong security-full security. In addition, the security of our scheme is reduced to a generalized assumption-Computation Diffie-Hellman(CDH) assumption instead of other strong assumptions.

A mobile ad hoc network has the computational and energy constraints, the general threshold cryptography does not suit it. In this paper, we consider a new kind of proper public encryption to the ad hoc networks: threshold broadcast encryption. A new construction of identity-based threshold broadcast encryption is proposed. In the proposed scheme, any user can dynamically join the system as a possible recipient, and the sender can dynamically choose the set of recipients and the threshold value t. Our new scheme achieves constant size private keys and O(n-t)-size ciphertexts. This is the first scheme which achieves short ciphertexts and full security in the standard model. Finally, we also show that it is provable security under n+1-Weak Decision Bilinear Diffie-Hellman Exponent (n+1-wDBDHE) assumption.

Biometric measurements are noisy and the existing techniques cannot be used directly to construct biometric-based scheme. Hence an error-tolerance property(Fuzzy) can be used to solve this problem. In this paper, a new biometric identity based signature scheme is proposed with the error-tolerance property. Our scheme is constructed in the standard model and achieves the selective identity security. In addition, the security of our scheme is reduced to a natural assumption-Computation Diffie-Hellman(CDH) assumption instead of other strong assumptions.