Authored by chunhua

update

## 安全控制
## 安全控制
### 消息完整性校验
### 消息完整性校验
![checksum](/path/to/img.jpg)
### 会话控制
![session control](/path/to/img.jpg)
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### 会话控制
![session control](http://git.dev.yoho.cn/yoho-documents/api-interfaces/blob/master/security/session-control.jpg)
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