Introduction to WWW

In 1989 a small group of people led by Tim Berners-Lee at CERN (European Organization for Nuclear Research) proposed the idea of World Wide Web(WWW) where the scientists across the world can share scientific documents irrespective of the underlying equipment. In 1991 WWW was practically implemented and released to the public.

The basic units of information in the WWW are documents or pages or resources. The documents contain text known as hypertext. Hypertext is text which can link to other documents on the Web. Primarily the documents shared through Internet using WWW used to contain text only. Later, images, audio, video and other forms of content were also included. This collection of content in a document is known as hypermedia.

World Wide Web and Internet same or different?
It is important to know that the Internet existed even before WWW was invented. Internet is a collection of computers and other devices which allows them to communicate with each other. WWW is a collection of software and protocols available on almost all of the computers in the Internet. Internet was useful through telnet, FTP, mailto and other protocols even before the invention of WWW. WWW just made it easier to access the services through Internet.

Security Concepts

Security in the web relate to protecting your sensitive data (like passwords, credit card numbers, PINs etc) from being accessed or manipulated by the people whom you think are not deemed to do so.

Most of the security concerns arise due to the vulnerabilities in the Internet and related technologies. To understand what are the security issues, consider an example of a transaction where you send your username and password to login to a website.

Security issues for this transaction are as follows:

Privacy – It should not be possible for a third-party to steal your data while it is being sent to a server.

Integrity – It should not be possible for a third-party to modify your data before reaching the server.

Authentication – Both sides of the communication should be able to identify each other’s identity.
Non-repudiation – Both sides must be able to prove legally that the message was sent and received.

First two issues, privacy and integrity can be supported by using encryption which is way to convert human readable information to non-human readable. There are several algorithms widely available for encryption among which the popular ones are RSA, DES, AES and Triple DES.

There is another dimension which raises various problems regarding the security of the data. It is through malicious programs. Hackers (people with evil intensions) create malicious programs known as viruses, worms, time bombs and others.

A virus is a malicious program which is transmitted through attachments of an e-mail or as a part of a software download that when executed on the victim’s computer, attaches itself with the other programs and makes them unusable or deletes data available in the memory or hard disk.

A worm, unlike a virus, has the ability of self propagation. Viruses and worms allows an attacker to gain control of the victim’s computer which in turn are used as a part of attacks known as DoS (Denial of Service) attacks.

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