Secretcodes(密碼)keepmessagesprivate.Banks,companies,andg...
問題詳情:
Secret codes (密碼) 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(落後) 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
知識點:七選五題型
題型:未分類
-
某商品進價是1000元,售價為1500元.為促銷,商店決定降價出售,但保*利潤率不低於,則商店最多降 元...
問題詳情:某商品進價是1000元,售價為1500元.為促銷,商店決定降價出售,但保*利潤率不低於,則商店最多降元出售商品.【回答】450元. 知識點:一元一次不等式題型:解答題...
-
默寫古詩名句,並寫出相應的作家、篇名。(12分)①像野馬在平原上賓士,像 ,...
問題詳情:默寫古詩名句,並寫出相應的作家、篇名。(12分)①像野馬在平原上賓士,像 ,像 。②五嶺逶迤騰細浪, 。(*《七律·長征》)...
-
予獨愛蓮之 , 。(周敦頤《愛蓮說》)
問題詳情:予獨愛蓮之 , 。(周敦頤《愛蓮說》)【回答】出淤泥而不染,濯清漣而不妖知識點:作家作品題型:填空題...
-
Chinahasbeenpushingthereformofpublichospitals_______al...
問題詳情: Chinahasbeenpushingthereformofpublichospitals_______allitscitizens.A.inchargeof B.forthepurposeof C.inhonorof ...
相關文章
- Mycousinwantstokeepslim.Shedoesexerciseeverymorningand ...
- Secretcodes(密碼)keepmessagesprivate.Banks,companies,and...
- 完形填空Theseyears,wecanseemoreandmorepeoplelikedancinginpu...
- 單項選擇。WheneverMaryreadsaninterestingstory,shecan'tkeepit...
- 單項選擇。WheneverMaryreadsaninterestingstory,shecan'tkeepit...
- Secretcodes(密碼)keepmessagesprivate。Banks,companies,andg...
- 單項選擇。WheneverMaryreadsaninterestingstory,shecan'tkeepit...
- UKPrimeMinisterDavidCameron’sMessageonChineseNewYear201...
- Speed-readingisanecessaryskillintheInternetage.Weskimov...
- 閱讀理解ThedesignerofAppleComputer,StevenJobs,wasnotquitesu...