对第一个基于格理论构造的模糊身份签名方案进行了深入分析,指出了它的安全性证明中存在的两个问题:1)对私钥提取查询的应答会导致Hash函数碰撞的产生;2)对于和挑战目标相同比特位数大于门限值的身份的签名查询无法应答.针对这些问题,给出了相应的改进方法,并且利用格上固定维数的格基代理方法,避免了原方案中维数的扩张,给出了一个私钥维数和签名维数更短的模糊身份格基签名方案.最后,给出了新方案的安全性证明. The first one is based on the lattice structure of the fuzzy identity signature scheme is analyzed in-depth, and pointed out that there are two problems in its security certificate: 1) The response to the private key extraction query will lead to the collision of Hash function; 2 ) Can not answer the signature query which has the same number of bits as the challenge target whose identity is greater than the threshold value.Aiming at these problems, corresponding improvement methods are given, and the lattice-proxy method with fixed dimension is used to avoid the original scheme In the expansion of the dimension number, a fuzzy identity-based signature scheme with a shorter dimension of the private key and a shorter signature length is given.Finally, the security proof of the new scheme is given.