Definition

As XML becomes a predominant means of linking blocks of information together, there is a requirement to secure specific information. That is to allow authorized entities access to specific information and prevent access to that specific information from unauthorized entities. Current methods on the Internet include password protection, smart card, PKI, tokens and a variety of other schemes. These typically solve the problem of accessing the site from unauthorized users, but do not provide mechanisms for the protection of specific information from all those who have authorized access to the site.

Now that XML is being used to provide searchable and organized information there is a sense of urgency to provide a standard to protect certain parts or elements from unauthorized access. The objective of XML encryption is to provide a standard methodology that prevents unauthorized access to specific information within an XML document.

XML (Extensible Markup Language) was developed by an XML Working Group (originally known as the SGML Editorial Review Board) formed under the auspices of the World Wide Web Consortium (W3C) in 1996. Even though there was HTML, DHTML AND SGML XML was developed byW3C to achieve the following design goals.

" XML shall be straightforwardly usable over the Internet.
" XML shall be compatible with SGML.
" It shall be easy to write programs, which process XML documents.
" The design of XML shall be formal and concise.
" XML documents shall be easy to create.

XML was created so that richly structured documents could be used over the web. The other alternate is HTML and SGML are not practical for this purpose.HTML comes bound with a set of semantics and does not provide any arbitrary structure. Even though SGML provides arbitrary structure, it is too difficult to implement just for web browser. Since SGML is so comprehensive that only large corporations can justify the cost of its implementations.

The eXtensible Markup Language, abbreviated as XML, describes a class of data objects called XML documents and partially describes the behavior of computer programs which process them. Thus XML is a restricted form of SGML

A data object is an XML document if it is well-formed, as defined in this specification. A well-formed XML document may in addition be valid if it meets certain further constraints.Each XML document has both a logical and a physical structure. Physically, the document is composed of units called entities. An entity may refer to other entities to cause their inclusion in the document. A document begins in a "root" or document entity