Tag: programming

Different Types of XML Parser

XML parser is a software module to read documents and a way to give access for their content. XML parser generates a structured tree to return the results to the browser. An XML parser resembles a processor that determines the construction and properties of the data. An XML document can be read by an XML parser to create an output to build a screen sort. There are numerous parsers available and some of these are listed below:

The Xerces Java Parser
The primary function of the Xerces Java Parser is the building up of XML-aware web servers
Also to ensure the integrity of e-business data expressed in XML, James Clark contributed this parser to the community.

XP and XT

XP is a Java XML and XT is an XSL processor. Both are written in Java.XP detects all non well formed files. It plans to function as most rapid conformant XML parser in Java and gives high performance. On the other hand XT is a set of tools for building program transformation systems. The tools include pretty printing; bundling

SAX

Simple API for XML (SAX) originated by the members of a public mailing list (XML-DEV).It gives an occasion based approach to XML parsing. It indicates that instead of going from node to node, it goes from event to event. SAX is event. Events contain XML tag, detecting errors etc, such as this reference.

It’s optimal for a small XML parser and applications that need fast. It must be used when all of the procedure must be performed economically and quickly to input components.

XML parser

It runs on any platform where there’s Java virtual machine. It’s sometimes called XML4J.It has an interface which allows you to have a chain of XML formatted text, decide the XML tags and rely on them to extract the tagged information.

Harold Evensen
http://www.uktv-online.com/

Important Authentication Solutions -Kerberos

Kerberos is one of the most important authentication systems available to developers and network architects. It’s aim is simple - to provide a single sign on to an environment comprising of multiple systems and protocols. Kerberos therefore allows mutual authentication and importantly secure encrypted communication between both users and systems. It’s different too many authentication systems in that it does not rely on security tokens but relies on each user or system to maintain and remember a unique password.

When a user authenticates against the local operating system, normally there is an agent running which is responsible for sending an authentication request to a central Kerberos server. This authentication server responds by sending the credentials in encrypted format back to the agent. This local agent then will attempt to decrypt the credentials using the password which has been supplied by the user or local application. If the password is correct, then the credentials can be decrypted and the user validated.

After successful validation the user is also given authentication tickets which allow them to access other Kerberos- authenticated services. In addition to this, a set of cipher keys is supplied which can be used to encrypt all the data sessions. This is important for security which is especially relevant when dealing with a wide range of different applications and systems with a single authentication system.

After validation is completed also, no further authentication is necessary - the ticket will allow access until it expires. So although the user does need to remember a password to authenticate, only one is required to access any number of systems and shares on the network. There are a lot of configuration options to finely tune Kerberos particularly in a Windows environment where Kerberos is used primarily to access Active Directory resources. You can restrict access based on a whole host of factors in addition to the primary authentication. It’s effective in authentication in a fluid environment where users may log on to many different systems and applications, even when these systems can keep changing their IP address (note: http://www.changeipaddress.net/ )

There is one single reason that Kerberos has become so successful, it’s because it’s freely available. Anyone can download and use the code free of charge, which means it’s widely utilised and is constantly developed and improved too. There are many commercial implementations of Kerberos such as from Microsoft and IBM (Global Sign On) these normally have additional features and a management system. There have been concerns over various security flaws in Kerberos however because it is open source these have all been fixed in the latest implementation Kerberos V.

George Hempseed

Author: BBC iPlayer in Ireland