The new scheme provides implicit key authentication and perfect forward secrecy etc.

该方案提供了隐含密钥认证和完善前向保密等安全属性.

But signcryption schemes cannot provide forward secrecy and public verifiability as the traditional method does.

然而签密方案不能像传统方法那样同时提供前向安全性和可公开验证性.