中文摘要：

针对目前已知的大多数多变量公钥签名方案都处于攻击之下的事实,对多变量公钥签名的一般模型进行分析,提出一种改进结构.通过借助另一秘密仿射变换,使公钥多项式并非像在原模型中直接对应于私钥合成,进而隐藏要签名的消息值,以减少攻击者所能获得的信息量,增强抗攻击能力.理论分析表明,改进的模型可以有效提高签名方案的安全性.最后,以中等域扩张型（MFE）多变量密码系统为例进行说明.

英文摘要：

Since most of the known multivariate public key signature schemes are under attacks, an improved signature model is proposed by analyzing the structure of the classical model. The method to redesign the model is to add another secret transformation so that the public key polynomials are not corresponding to the composition of the private keys, that is not the case in classical model, and the message value is hidden, then the amount of information obtained by attacker are reduced, and the scheme performance against attacks is enhanced. Analysis shows that the improved model can strengthen the security of various multivariate signature schemes. Finally, medium-field extension （MFE） multivariate cryptosystem is taken as an example to illustrate the idea.