O-LevelComputer ScienceData Representation2210/12 · Oct/Nov 2020 · Q130 Marks

Tina is creating a website for charity events. She uses HTML to create the website.

(a)State what is meant by HTML.[1]
(b)(i)State whether background colour is an example of structure or presentation, in the website.[1]
(b)(ii)The hexadecimal colour code #43B7F0 is stored in three 8-bit registers. Give the 8-bit binary values for each part of the hexadecimal code. 43 B7 F0[6]
(c)(i)State whether the microphone is an input or output device.[1]
(c)(ii)She wants to compress the recording to make sure that the file is as small as possible for the website. Identify which type of compression she should use and describe how this would compress the file for the website. Type of compression Description[4]
(c)(iii)Give two benefits of compressing the file for the website. Benefit 1 Benefit 2[2]
(d)(i)Identify the two layers that are present in the TLS protocol. Layer 1 Layer 2[2]
(d)(ii)Explain how data is sent securely using the TLS protocol.[6]
(e)(i)Identify three security threats to her web server that Tina might be concerned about. 1. 2. 3.[3]
(e)(ii)Tina installs a proxy server to help protect her website from security threats. Describe how the proxy server will help protect the website.[4]

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2020). The mark or mark type is shown in brackets.

[1] Any one from: Hypertext Mark-up Language; Web authoring language // language used to write/create websites/web pages
[1] Presentation
[6] One mark per each nibble: 43: 0100 0011; B7: 1011 0111; F0: 1111 0000
[1] Input
[1] One from: Lossy (compression)
[3] Any three from: A (compression) algorithm is used; Removes redundant/unnecessary data from the file; Removes sounds that cannot be heard by the human ear/background noise; Reduces sample rate; Reduces sample resolution; Data is permanently removed // original file cannot be re-instated; Perceptual music shaping is used
[2] Any two from: Quicker for her to upload; Quicker for users to download; Won't slow website down as much when loading; Takes up less storage space
[1] Handshake (layer)
[1] Record (layer)
[6] Any six from: Client/browser requests secure connection to server; Client/browser requests the server to identify itself; Server provides a digital certificate; Client/browser validates the certificate; Client/browser send signal back to server (to begin transmission); Session caching can be used; A session key is generated; Encryption method is agreed // data is encrypted
[3] Any three from: Hacking; Denial of service (DoS) attack; Virus; Malware. NOTE: Three different type of malware can be awarded
[4] Any four from: Acts as a firewall; Monitor/filters/examines incoming and outgoing traffic; Rules/criteria for traffic can be set // blacklist/whitelist set; Blocks any traffic that does not meet criteria; and can send a warning message to the user; Stop the website failing in a DoS attack // DoS attack hits the proxy server and not the webserver