Robust ID-based threshold signcryption scheme from pairings

Recently bilinear pairings on elliptic curves have raised great interest in cryptographic community. Based on their good properties, many excellent ID-based cryptographic schemes have been proposed. However, in these proposed schemes, the private key generator should be assumed trusted, while in real environment, this assumption does not always hold. To overcome this weakness, in this paper, we will use the threshold technology to devise a secure ID-based signcryption scheme. Since the threshold technology is adopted not only in the master key management but also in the group signature, our scheme can achieve high security and resist some malicious attacks under a certain threshold.