Homework Revision

Homework 12


1. PHP – pre-processed hypertext
2. Advantage – No need for client side plug-ins. The PHP script is executed on the web server, so only the web server needs plug-ins.
Advantage – Slows down the server.
3. A browser creates cookies to keep a record for the website owner to see how many people visit their site. They are updated so that websites can track users and see what websites they view.
4. A browser retrieves the HTML of the website and interprets it to show a viewable web page.
5. SSL – Secure socket layer.
6. Secure servers are given a certificate, link is encrypted as well as the data and a combination of send and receive ports.
7. Can a web page be viewed on more than one web browser and does the browser have the proper plug-ins to view the web page.
8. RSA is asymmetric and requires a lot of calculations whilst PGP is symmetric and uses 2 different keys to encode and decode. PGP is better as it does not require numerous complex calculations, PGP is more suited to handle internet traffic and is faster compared to RSA.
9. A public key is widely distributed to the public and a private key must be sent with the public key to ensure the information can be decoded.
Information systems homework


1. 3 functions of a browser: to allow web pages to be viewed
To convert html into a readable website
Forward and back buttons
2. Client side scripting is when the client uses scripting in order to be able to change a website because html is static and cannot be changed once it has been entered.
B)
3. Cookies allow a web server to send and receive information. A cookie is a file tat contains only one line of text, and is stored on the web servers or the user’s hard drive.
b) They keep track of the sites that have been visited and allow the web server to keep a hit counter of how many people have visited that site.
c) Site-tracking software collects and analyses the data that is generated by Internet traffic. The simplest type is a hit counter, which can be incorporated into a web page.
4. Credibility –
Bias – yes, as it would be telling people that the food is delicious and better than any other fast-food restaurant.
Accuracy – it would be as accurate as they could get the information.
b) The legality of this page is that it does not tell of the food risks involved when eating this food.
5. RSA encryption – this uses a numerous complex mathematic problem to scramble data.
PGP encryption – this uses RSA to encode the cipher key, it is slow but it does not include the numerous mathematic problem.
6. Educational entertainment which helps people to learn by making a subject fun. This usually include games and activity sheets.
b) Academic – educational website giving information about primary, secondary, colleges and universities.
c) Commercial – A company website advertising a product or service.
d) Personal – a website made for someone’s favourite band.

Homework

1. An Ip's purpose is to uniquely identify a network.

2. a) A data packet is a piece of information which is split into small packets in order for it to be sent from the sender to the reciever.
b) Document which is to be sent, source ip address and destination ip address.
c) Switching packets works by sending the packets through routers which use a routing table to identify which routes are the best for sending the packets.

3. Protocol
Port number
Domain Name
Path
File Identifier
b)

4. A proxy server is a computer that offers a computer network service to allow clients to make indirect network connections to other network services.
b) It allows websites to be stored without it directly contacting the internet everytime for a specific website and
c) The DNS uniquely identifies the ip address instead of the website address itself.
d) It will contact other DNS databases until it either finds the website he wants or an error message will appear saying that the website could not be found.

5. Class C
b) Subnets allow a network to be classed as a different network in order to allow more people to work with the network.