江苏省常州市横山桥高级中学10-11学年高二上学期期中考试（英语Ifyouandyourfriendswishtoshareasecretyoucanwriteitincodeandnooneelsewillbeabletoreadit.Codesareonewayofwritinginsecrets.Ciphers(暗码)areanother.Inthecodeeachwordiswrittenasasecretcodeorwordnumber.Inaciphereachletterischanged.Codesandciphershaveplayedanimportantroleinthehistoryoftheworld.JuliusCaesartheRomanrulerwhodefeatedalmostallthecountriesinEuropeabout2000yearsagousedacipherwhenhesentsecretmessagestohistroops.DuringAmericanRevolutionGeorgeWashington’sspiesusedakindofcodetosendhiminformationabouttheenemybeforehismilitary(军事的)action.InWorldWarIItheAmerican“broke”orfiguredoutJapan’smostimportantnavycodesandgotenoughinformationtodestroyapowerfulJapanesefleet(舰队).Storekeepersusedcodestomarktheirgoods.Thecodesshowedhowmuchwaspaidforthegoodsorwhentheywereaddedtothestock.Businessmenusedcodestohideplansfromtheirbusinessenemies.Sometimespersonallettersordiarieswerewrittenincode.Manypeopleenjoyedfiguringoutcodesandcipherssimplyasahobby.Inthe16thcenturycodesandcipherswereverypopularamongscientists.Theywrotemessagestoeachotherincodesothatnooneelsewouldlearntheirsecrets.GeronimoGardanoanItalianastrologer(星相家)mathematiciananddoctorinventedthetrelliscipher.Hetooktwosheetsofpaperandcutexactlythesameholesineachone.Thenhesentonesheetwhichhecalledatrellistoafriendandkepttheotherforhimself.Wheneverhewantedtowriteamessageheputhistrellisovertheothersheetofpaperandwrotethesecretmessagethroughtheholes.Thenheremovedthetrellisandfilledtherestofthepaperwithwordsthatwouldmakesense.WhenhisfriendsreceiveditHeputhistrellisoverthewritingandreadthesecretmessage.Codesand71_______72.________waystosendinformationDifferent73_______lThetrelliscipherwasthe79_____ofGardano.lSomescientistsuseditto80_____secretinformation.◆In74______codeswereusedtoachievebusinesspurposes.◆Manypeopleenjoyedfiguringoutcodesasan75________.◆Inthe76________tomakethemilitaryleaders77______ofthesituationofthewarcodeswerealsousedto78_______thewar.