精选优质文档-倾情为你奉上历年高考试题分项解析之专题七选五1【2016全国新课标I】根据短文内容，从短文后的选项中选出能填入空白处的最佳选项，选项中有两项为多余选项。 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. 71 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.
