Internet Technologies

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The World Wide Web

In recent years the Internet has been improved greatly by overlaying it with the World Wide Web.

This is a system where data and information can be displayed as pages. These pages can contain text, images and other graphics, sounds, animations and video.

Each page is hyperlinked (linked by mouse clicks on the highlighted area) to others on the same web site, and/or to other pages on other web sites.

Webpage 1.jpg

A website is an area on a server created by an organisation or individual. It is created from individual web pages. A museum website, for example, will include pages about the museum as well as a knowledge base of facts and figures about the contents of the museum.

The Web is as difficult to find things on as the original standard Internet. If you don't know the web address of a site then it is difficult to find the site. Software has been developed to address this problem - the search engine. Search engines will find a web address for you based on search terms (words or phrases) connected with the site you are trying to find.

Email

Email is a way of transmitting written documents electronically through telephone lines.

Email.jpg

The email is created on a source computer and sent to a holding computer known as a mail server. When the user of the computer with the receiving email address logs on, they are alerted to the fact that they have email. The mail server releases the email to the receiving computer so the user can read it.

Multimedia

This is where more than one method of presenting information is used at the same time, each method contributing to the presentation as a whole. One of the most common multimedia methods is combining film or animation with sound to produce a video presentation.

Here is an example of multimedia on the Internet. It uses video film with music edited over the original talking. The film was downloaded from a digital video camera.

(Please note that this is a Real Player file. You may need to save it to your desktop and open it in Real Player.)

Encryption

A lot of confidential material is sent using Internet technologies. Often this material is sent by email.

Ordinary emails can be tampered with quite easily. Hackers can intercept them, read them and change them without anyone knowing. Viruses can redirect emails or even destroy them.

It is not possible to stop hackers and viruses, but it is possible to prevent them from reading emails. This is done by encrypting the contents of the email.

Encryption turns the normal text of an email into a secret code. The code can only be translated back into readable text if the correct key is used. The key is a type of password that enables decoding.

A well encrypted document is almost impossible to crack without super-computers and a lot of time (up to thousands of years).

Below is an example of encrypted text. The original text was typed into Notepad. This text was ‘Hello world’. It was then encrypted using the word ‘phone’ as the key.

Before encryption

Before encrypt.jpg

After encryption

After encrypt.jpg