中文摘要：

在一个安全的代理签名方案中，只有指定的代理签名人能够代表原始签名人生成代理签名．基于椭圆曲线离散对数问题，纪家慧和李大兴提出了一个代理签名方案和一个代理多签名方案，陈泽雄等人给出了另外两个代理多签名方案．但是，在他们的方案中，原始签名人能够伪造代理签名私钥．为了抵抗原始签名人的伪造攻击，改进了代理签名密钥的生成过程，并对改进的方案进行了安全性分析．

英文摘要：

In a secure proxy signature scheme, only the designated proxy signer could create a valid proxy signature on behalf of the original signer. Based on the elliptic curve discrete logarithm problem, Ji and Li proposed a proxy signature scheme and a proxy multi-signature scheme and Chen et al. proposed two proxy multi-signature schemes. However, in their schemes, the original signer can forge proxy secret key. To eliminate the original signer＇ s forgery attacks, a modification of the proxy key generation stage is proposed. Security analysis of the improved scheme is also presented.