All we do in this paper focus on the certificate function of pki , and the innovation is that the improved pki system can publish not only common public key certificate , but also wireless certificate , attribution certificate and nested certificate which is for improving system verification performance , this multi - function can meet user ' s large and wide application needs 本人所作的工作主要是围绕pki系统的证书服务这一特征,创新点在于实现的系统既具备普通证书服务,同时又能颁发无线证书、属性证书以及为了改善系统验证性能而存在的嵌套证书,能适应当前用户多而广的应用需求。