问题
单项选择题
数字证书是一条数字签名的消息，它通常用于 ______。
A．证明某个实体的公钥的有效性
B．证明某个实体的私钥的有效性
C．证明证书的签名的有效性
D．证明证书的发放者是真正的，而不是冒充的
答案
参考答案：A
解析：[知识点] 密钥管理[评析] 数字证书是一条数字签名的消息，它通常用于证明某个实体的公钥的有效性。
搜题请搜索小程序“爱下问搜题”
数字证书是一条数字签名的消息，它通常用于 ______。
A．证明某个实体的公钥的有效性
B．证明某个实体的私钥的有效性
C．证明证书的签名的有效性
D．证明证书的发放者是真正的，而不是冒充的
参考答案：A
解析：[知识点] 密钥管理[评析] 数字证书是一条数字签名的消息，它通常用于证明某个实体的公钥的有效性。
| 阅读理解，信息归纳。 | |||||
| Last Tuesday, a little girl died after eating some fried chicken. Her father bought the chicken for her from a street seller in Fenzhuang Village, Fengtai, Beijing. After testing the girl, the doctor said she was poisoned (中毒) by nitrites (亚硝酸盐). Some experts suggest that we should buy foods with QS signs. They are safer. After hearing about the accident, many people feel more worried about the food safety because there have been many food safety problems in our country these years. For example, poisonous (有毒的) rice, oil, milk and so on have been found out recently. People feel quite afraid because these poisonous foods are rather bad for their health and even kill them. They want the government to do something to stop such poisonous foods and drinks appearing again so that they can have safe and healthy foods and drinks. | |||||
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