2022年计算机经典英语短文阅读.docx
2022年计算机经典英语短文阅读英语 短文 计算机 计算机英语一 CMS is used to digitally sign or encrypt arbitrary messages. CMS describes an encapsulation syntax for data protection. It supports digital signatures and Encryption. The syntax allows multiple encapsulation, so one encapsulation envelope can be nested inside another. Likewise, one party can digitally sign some previously encapsulated data. It also allows arbitrary attributes, such as signing time, to be authenticated along with the message content, and provides for other attributes such as counter-signatures to be associated with a signature. CMS被用于数据签名或者随意消息加密中。CMS供应了一套用于数据爱护的数据封装语法。该语法支持数据签名和数据加密。该语法允很多重封装，所以一封数据信封能被另外一封数据信封所封装。同样的，该语法封装数据的部分数据位可以用来表示被封装数据。也允附加一些属性如签名时间，它和内容信息一起用于鉴别信息;计数器属性，它为其它属性供应计数信息。 计算机英语二 XDM is the foundation of XPath 2.0 and defines the Data Model for XPath 2.0 (and consequently XQuery 1.0 and XSLT 2.0, which are both based on XPath 2.0). XDM is built on top of the XML Info set (the abstraction of an XML document), PSVI (type annotations in the XML Info set as the result of XML Schema validation), the simple data types of XML Schema, and additional concepts. The most important additional concept is that of a sequence, which embraces both simple data types and the XML-derived nodes. XDM是XPath2.0的基础，它定义了XPath2.0的数据模型(因此XQuery 1.0 、XSLT 2.0也就基于XPath 2.0)。XDM 建立在XML信息集(从XML文档中抽取)和PSVI(作为确认XML Schema结果的XML信息集合的注释类型)的顶端、属于简洁的XML Schema的数据类型、是一个附加的概念。其中，它最重要的附加概念就是依次，即包括简洁数据类型和XML的源节点。 计算机英语三 Internet technical specifications often need to define a format syntax and are free to employ whatever notation their authors deem useful. Over the years, a modified version of BNF, called ABNF, has been popular among many Internet specifications. It balances compactness and simplicity with reasonable representational power. 互联网技术规范常常须要定义一种格式化语法并能自由地运用作者认为是有用的任何符号。多年来，巴克斯范式(BNF)的一个修订版，即扩展巴克斯范式(ABNF)，已经在很多互联网规范中流行。该版本平衡了压缩性和简洁性，具有合理的表达实力。 第3页 共3页第 3 页 共 3 页第 3 页 共 3 页第 3 页 共 3 页第 3 页 共 3 页第 3 页 共 3 页第 3 页 共 3 页第 3 页 共 3 页第 3 页 共 3 页第 3 页 共 3 页第 3 页 共 3 页
