An Efficient Provably Secure Certificateless Signcryption without Random Oracles

Abstract

Although most of existed signcryption schemes proven secure were proposed in the random oracle, however, it always could not be able to construct the corresponding schemes in the practical application. By analyzing several certificateless signcryption schemes in the standard model, it was pointed out that they are all not secure. Based on Au’s scheme, a new proven secure certificateless signcryption scheme was presented in the standard model by using bilinear pairing technique of elliptic curves. In the last, it was proved that the scheme satisfied indistinguishability against adaptive chosen ciphertext attack and existential unforgeability against adaptive chosen message and identity attack under the complexity assumptions, such as decisional bilinear Diffie-Hellman problem. So the scheme was secure and reliable.