Signcryption is a cryptographic primitive that performs encryption and signature in a single logical step more efficiently than signthen-encrypt approach. Till now, various kinds of signcryption schemes have been proposed. Among them, the requirement of signcrypter’s privacy protection is needful in some practical applications. In this paper, a new identity-based anonymous signcryption scheme from bilinear pairings, which is the organic combination of identity-based ring signature and encryption scheme, is proposed. The proposed scheme is indistinguishable against the chosen ciphertext attack under the Decisional Bilinear Diffie-Hellman assumption in the random oracle model. Its unforgeability relies on the computational Diffie-Hellman problem. Compared with the previous schemes, the new scheme is more efficient in computation.
