下列选项中，关于加密与解密算法的描述不正确的是( )。
A．加密算法是相对稳定的
B．解密算法所使用的密钥称为解密密钥
C．加密算法一定要做好保密工作
D．对密文解密时采用的一组规则称为解密算法
参考答案：C
解析： 对明文进行加密时采用的一组规则称为加密算法。对密文解密时采用的一组规则称为解密算法。加密算法和解密算法通常都是在一组密钥控制下进行的，加密算法所使用的密钥称为加密密钥，解密算法所使用的密钥称为解密密钥。加密算法是相对稳定的。在这种意义上，可以把加密算法视为常量，而密钥则是一个变量。加密算法实际上很难做到绝对保密，因此现代密码学的一个基本原则是一切秘密寓于密钥之中。
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| A gentle wind blew through Jennifer's hair. The golden red sun was 1. She was on the beach, looking up at the ball. She was amazed by its 2 , deep red in the middle, 3 fading into yellow. She could hear nothing but the 4 and the seagulls flying up above in the sky. The atmosphere 5 her. After all she had been through, this is what she 6 . "It's getting late,"she thought,"I must go home, my parents will be 7 where I am." She wondered how her parents would react, when she got home after the three days she was 8 . The sun had set by now and it was getting 9 . She tried to imagine having her favorite 10 on until she saw her front door. It seemed different. 11 had taken care of the outside garden for days. She was 12 : her father was usually so strict about keeping everything clean and tidy, and now… It all seemed 13 . She couldn't understand what was going on. She entered she 14 . First,she went into the kitchen where she saw a(n) 15 written by her father. It said:"Dear Ellen,there is some coffee ready,I went 16 ." Ellen was her motherbut-where was she? On the right side of the hallway was her 17 room. She went in. Then she saw her mother,lying on the bed sleeping. Her 18 looked so tired,as if she hadn't 19 for days. She was really pale. Jenny just fell asleep beside her. When Jennifer woke up she found something 20 . She was in her cozy bed in her nightclothes. It felt so good being back home. Suddenly she heard a voice. "Are you feeling better now, dear? You know you got us very, very scared." | ||||
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