Robust signcryption scheme

The previous ID-based signcryption schemes have some drawbackes,such as the signcryption can be forged;the sign-cryption can be tampered;the signcryption can't be public verified,and etc.In this paper,the security of the M-W scheme is analyzed.The bilinear parings are adopted to propose a robust ID-based signcryption scheme.The proposed scheme not only has some characters,such as public verifiability,non-repudiation and forward security,but also has the charaters of unforgeability and robustness.The proposed scheme only needs four bilinear parings,and needn't the multiplication operation and power operation in G2.It is more efficient than the other ID-based signcryption schemes.