A-LevelComputer ScienceSecurity9618/12 · May/June 2024 · Q314 Marks

An assessment board scans exam papers and stores the digitised papers on a server. Exam markers download the digitised papers to mark. The exam markers then upload the mark for each paper.

(a)(i)Identify one other security measure that helps to protect the server from hackers. Describe how the security measure works. Security measure Description[3]
(a)(ii)Identify one security measure that helps to protect the data when it is being transmitted to its destination. Describe how the security measure works. Security measure Description[3]
(b)The exam markers use software that operates as a thin-client to mark the exam papers. Complete the table by identifying two characteristics of a thin-client. Describe how each characteristic will be used in this software. Thin-client characteristic Description of use in this software 1 2[4]
(c)(i)Describe the role of routers in the transmission of data through the internet.[2]
(c)(ii)Describe the role of the PSTN (Public Switched Telephone Network) in the transmission of data through the internet.[2]

Mark scheme

Marking points from the official mark scheme (May/June 2024). The mark or mark type is shown in brackets.

[1] (a)(i) Security measure: Firewall
[1] (a)(i) Description: Checks incoming connections
[1] (a)(i) Description: against criteria
[1] (a)(i) Description: Blocks data from entering specific ports
[1] (a)(i) Description: Blocks data that does not meet whitelist that meets blacklist
[1] (a)(i) Security measure: Proxy server
[1] (a)(i) Description: Prevents devices accessing the web server directly
[1] (a)(i) Description: Intercepts any requests
[1] (a)(i) Description: Forwards the request using its own IP address
[1] (a)(i) Description: Screens returning data before sending it to the user
[1] (a)(ii) Security measure: Encryption
[1] (a)(ii) Description: Encodes/scrambles data
[1] (a)(ii) Description: so if it is intercepted it cannot be understood
[1] (a)(ii) Description: Algorithm/key is required to decode the data
[1] (b) Characteristic 1: Data is not stored on the client computer
[1] (b) Description 1: Exam papers are stored on the server and not on the examiner's computer // exam papers are not permanently stored on the examiners' computers
[1] (b) Characteristic 2: Client computer is reliant on access to server
[1] (b) Description 2: Examiners cannot mark if their device cannot access the server / the server 'goes down'
[1] (b) Characteristic 3: Client computer heavily reliant on network/internet connection
[1] (b) Description 3: The marking software will not operate without network/internet access
[1] (b) Characteristic 4: Client computer requires few local resources/memory
[1] (b) Description 4: Examiners can use devices with low resources and the marking software will still function
[1] (b) Characteristic 5: Client computer performs minimal functions/processes
[1] (b) Description 5: The marking software transmits requests, the server responds and sends the response to the user
[1] (c)(i) Receives packets from internet
[1] (c)(i) Analyses the destination IP address of each packet
[1] (c)(i) Forwards the packet towards its destination
[1] (c)(i) using the routing table
[1] (c)(i) Maintains/updates the routing table
[1] (c)(i) Finds the most efficient route to the destination
[1] (c)(ii) The PSTN consists of many different types of communication lines
[1] (c)(ii) therefore the digital data may need to be converted into a different form/analogue signal
[1] (c)(ii) Data is transmitted in both directions at the same time // duplex data transmission
[1] (c)(ii) Using a PSTN the communication passes through different switching centres/ISPs