Questions 8 and 11 are based on the news reportyou have just heard.(1) (单选题)What does the woman say is the disadvantage of working from home?A.Her children's disruption.B.quiet atmosphere.C.A sense of isolation.D.Longer working hours.(2) (单选题)What does the man say is counterproductive to getting work done in the library?A.It doesn't offer coffee.B.It's too quiet.C.It doesn't have free Wi-Fi.D.It lacks the material he needs.(3) (单选题)What does the woman like about doing one's work in a cafe?A.The sense of being out in the world.B.The coffee it provides.C.The coffee tables.D.The comfortable working condition.(4) (单选题)What is most annoying for cafe owners according to the woman?A.People don't order anything.B.People bring their laptops and paperwork.C.People occupy valuable table space in quiet times.D.People of two occupy a table for six.A. DES算法B. DSA算法C. RSA体制D. PES算法正确答案：C 解析：RSA体制被认为是迄今为止理论上最为成熟完善的一种公钥密码体制。该体制的构造基于如下的基本事实：寻找大素数是相对容易的，而分解两个大素数的积在计算上是不可行的。RSA算法的安全性建立在难以对大数提取因子的基础上。所有已知的证据都表明，大数的因子分解是一个极其困难的问题。