Secretcodes(密码)keepmessagesprivate.Banks,companies,andg...
问题详情:
Secret codes (密码) keep messages private. Banks, companies, and government agencies use secret codes in doing business, especially when information is sent by computer.
People have used secret codes for thousands of years. 31 Code breaking never lags(落后) far behind code making. The science of creating and reading coded messages is called cryptography.
There are three main types of cryptography. 32 For example, the first letters of “My elephant eats too many eels” Spell out the hidden message “Meet me.”
33 You might represent each letter with a number, for example, Let’s number the letters of the alphabet, in order, from 1 to 26. If we substitute a number for each letter, the message “Meet me” would read “13 5 20 13 5.”
A code uses symbols to replace words, phrases, or sentences. To read the message of a real code, you must have a code book. 34 For example, “bridge” might stand for “meet” and “out” might stand for “me.” The message “bridge out” would actually mean “Meet me.” 35 However, it is also hard to keep a code book secret for long. So codes must be changed frequently.
A. It is very hard to break a code without the code book.
B. In any language, some letters are used more than others.
C. Only people who know the keyword can read the message.
D. As long as there have been codes, people have tried to break them.
E. You can hide a message by having the first letters of each word spell it out.
F. With a code book, you might write down words that would stand for other words.
G. Another way to hide a message is to use symbols to stand for specific letters of the alphabet.
【回答】
DEGFA
知识点:七选五题型
题型:未分类
-
下列各组词语中加点的字注音完全正确的一项是( )A.吮吸(yǔn)札记(zhá) 艾蒿(hāo)剔除(t...
问题详情:下列各组词语中加点的字注音完全正确的一项是( )A.吮吸(yǔn)札记(zhá) 艾蒿(hāo)剔除(tì) 垂涎三尺(xián)B.睥睨(bì) 蛮横(hèng)自诩(xǔ) 畏葸(xǐ) 聊以慰藉(jí)C.龟裂(jūn)讥诮(qiào)脸颊(jiá)监生(jiàn)戛然而止(jiá)D.蹩进(bì) 瞭望(lià...
-
下列句子中没有运用拟人修辞手法的一项是( ) A.我们的春雁每天都要去玉米地作一次旅行,但绝不是偷偷摸摸进行的...
问题详情:下列句子中没有运用拟人修辞手法的一项是( ) A.我们的春雁每天都要去玉米地作一次旅行,但绝不是偷偷摸摸进行的。B.每次出发前,都有一场高声而有趣的辩论,而每次返回之前的争论则更为响亮。C.3月的大雁则不同。尽管它们在冬天的大部分时间里都可能受到*击,但...
-
下列词语中加点字的读音完全正确的一项是 A.绮丽(qǐ) 祈祷(qí) 既往不咎...
问题详情:下列词语中加点字的读音完全正确的一项是 A.绮丽(qǐ) 祈祷(qí) 既往不咎(jiù) B.翘首(qiáo) 脂肪(zhǐ) 水涨船高(zhànɡ)C.诘责(jié) 鸟瞰(kàn) 首当其冲(zhònɡ) ...
-
打秋千时,为使秋千越荡越高,人应有一个从直立到蹲下,又从蹲下到站直的过程.则打秋千时 A.人的机械能是守...
问题详情:打秋千时,为使秋千越荡越高,人应有一个从直立到蹲下,又从蹲下到站直的过程.则打秋千时 A.人的机械能是守恒的 B.人应在最低点站起来 C.人应在最高点站起来 D.人在最低点时失重【回答】C知识点:未分类题型:选择题...
相关文章
- 完形填空Theseyears,wecanseemoreandmorepeoplelikedancinginpu...
- Speed-readingisanecessaryskillintheInternetage.Weskimov...
- 单项选择。WheneverMaryreadsaninterestingstory,shecan'tkeepit...
- 单项选择。WheneverMaryreadsaninterestingstory,shecan'tkeepit...
- Mycousinwantstokeepslim.Shedoesexerciseeverymorningand ...
- Secretcodes(密码)keepmessagesprivate.Banks,companies,and...
- 单项选择。WheneverMaryreadsaninterestingstory,shecan'tkeepit...
- Secretcodes(密码)keepmessagesprivate。Banks,companies,andg...
- 阅读理解ThedesignerofAppleComputer,StevenJobs,wasnotquitesu...
- UKPrimeMinisterDavidCameron’sMessageonChineseNewYear201...