一个健壮的签密方案

已有的基于身份的签密方案存在着签密能被伪造、能被篡改、不能公开验证等缺陷。分析了M-W方案的安全性，并利用双线性对提出了一个健壮的基于身份的签密方案。提出的方案不仅具有公开验证性、不可否认性、前向安全性，而且还具有可伪造性和健壮性。提出的方案只需要4个对运算，没有G2乘法运算和幂运算，比其他基于身份的签密方案效率更高。

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.