Ifyouandyourfriendswishtoshareasecret,youcanwriteitinco...
问题详情：Ifyouandyourfriendswishtoshareasecret,youcanwriteitincode,andnooneelsewillbeabletoreadit.Codesareonewayofwritinginsecret.Ciphers（暗码）areanother.Inacode,eachwordiswrittenasasecretcodeorcodenumbe...