2 Gurdeep takes high definition photographs using a digital camera. She has set up a website where users can view thumbnails of her photographs. A thumbnail is a small version of the high definition photograph. (a) Gurdeep compresses the high definition photographs to create the thumbnails. She uses lossy compression. Describe how lossy compression creates the thumbnails. … … … … … … [3] (b) Gurdeep sets up a web server to host her website. She reads about an Internet Protocol (IP) address, a Media Access Control (MAC) address and a Uniform Resource Locator (URL). Draw a line to connect each term to the correct example. Term Example IP address 192.168.0.255 MAC address https://www.cambridgeinternational.org URL 00:15:E9:2B:99:3C [2] (c) Users can buy the high definition photographs from the website. When a user buys a high definition photograph, a Secure Socket Layer (SSL) connection is created. (i) Give one benefit of using an SSL connection. … … [1] (ii) Explain how the SSL connection is created. … … … … … … … … [4]

2(a) Any three from: − A compression algorithm is used − Data will be lost/deleted permanently // original file cannot be recreated − Reduce the range of colours used / colour depth / bits per pixel − Reduce the number of pixels / image resolution removes data that will not be noticed by the user // removes unnecessary data 3 2(b) 1 mark for 1 line, 2 marks for 3 lines Term Details IP address 192.168.0.255 MAC address https://www.cambridgeinternational.org URL 00:15:E9:2B:99:3C 2 2(c)(i) − Data if intercepted cannot be understood // Data is encrypted // Data is scrambled // uses keys to encode/decode data 1 2(c)(ii) Four from: − Uses (digital) certificates − ….requested from web server by browser/client // browser/client asks web server to identify itself − Server send SSL/digital signature to browser/client − Client and server agree on encryption method to use − … that contains the server's public key − Browser checks authenticity of certificate… − … then session key is generated − … the transaction will begin // sends signal to server to start transmission 4 (a) To earn marks, you need to describe how lossy compression works, mentioning that a compression algorithm is used, data is permanently lost (meaning the original cannot be recreated), and it reduces color depth or image resolution by removing data not easily noticed by the user. (b) You must correctly draw lines connecting each term (IP address, MAC address, URL) to its corresponding example. (c)(i) To score this mark, you need to explain that encryption makes data unreadable if intercepted, or that it scrambles data using keys. (c)(ii) You need to describe four steps of the SSL/TLS handshake process, such as the use of digital certificates, the server sending its certificate, the client and server agreeing on an encryption method, and the generation of a session key before the transaction begins.

3 A firewall can be used to help keep the data secure that is stored on a computer. (a) The given paragraph describes how the firewall operates to help keep the data secure. Complete the paragraph using the most appropriate terms from the given list. Not all of the terms on the list need to be used. • Accept • Criteria • Hacking • Input • Network • Outgoing • Output • Processor • Reject • Software • Store • Storage A firewall can be … or hardware based. It monitors traffic between the computer and the … The user sets … for the traffic. The firewall will … or … the traffic based on this. It can help prevent … and malicious software that could be a threat to the security of the data. [6] (b) Identify three other methods that could be used to keep the data secure. Method 1 … Method 2 … Method 3 … [3]

3(a) One mark per each correct term in the correct order. − Software − Network − Criteria − Accept // reject − Reject // accept − Hacking 6 3(b) Any three from: − Password − Biometrics (device) − Encryption − Physical methods (e.g. locks) − Two-factor authentication // Two-step verification − Anti-viruses 3 For 3(a), you must correctly fill in all six blanks in the paragraph with the most appropriate terms from the provided list, in the correct order. For 3(b), you need to identify three distinct methods, other than a firewall, that can be used to keep data secure.

4 Two internet risks are phishing and pharming. Describe what is meant by phishing and pharming. Phishing … … … … … … Pharming … … … … … … [6]

4 Any six from: Phishing − Legitimate looking email sent to user − encourages user to click a link that directs user to a fake website − User encouraged to enter personal details into a fake website // designed to obtain personal details from a user Pharming − Malicious code/malware is downloaded/installed // software downloaded without users' knowledge − … that re-directs user to fake website (when legitimate URL entered) − User encouraged to enter personal details into a fake website // designed to obtain personal details from a user 6 To earn marks, you must provide a clear description of phishing, explaining it involves legitimate-looking emails leading to fake websites to obtain personal details. You also need to describe pharming, explaining it involves malicious code redirecting users to fake websites even when a legitimate URL is entered, also to obtain personal details.

4 Three types of Internet security risk are virus, spyware and denial of service (DoS) attack. (a) Six statements are given about Internet security risks. Tick (3) to show whether the statement applies to virus, spyware or denial of service. Some statements may apply to more than one Internet security risk. Statement Virus (3) Spyware (3) Denial of service (3) captures all data entered using a keyboard can be installed onto a web server prevents access to a website is malicious code on a computer is self-replicating damages the files on a user’s hard drive [6] (b) Identify three other types of Internet security risks. 1 … 2 … 3 … [3] (c) Some Internet security risks can maliciously damage data. Data can also be damaged accidentally. State three ways that data could be accidentally damaged. 1 … 2 … 3 … [3]

4(a) One mark per each correct row. Statement Virus () Spyware () Denial of service () captures all data entered using a keyboard  can be installed onto a web server   prevents access to a website  is malicious code on a computer   is self-replicating  damages the files on a user’s hard drive  6 4(b) Any three from: − Phishing − Pharming − Hacking // cracking 3 4(c) Any three from: − Human error − Power failure/surge − Hardware failure − Software failure − Fire − Flood 3 (a) For each statement, you must correctly tick the box(es) corresponding to the Internet security risk(s) (virus, spyware, denial of service) it applies to. (b) You need to identify three distinct types of Internet security risks other than virus, spyware, or denial of service. (c) You must state three different ways that data can be accidentally damaged, such as human error or power failure.

4 Spencer finds out that his online music account has been accessed by an unauthorised person. He believes his personal details for the account were obtained using phishing. (a) Explain how the personal details could have been obtained using phishing. … … … … … … [3] (b) Give two other Internet security risks that could have been used to obtain the personal details. 1 … 2 … [2]

4(a) − Legitimate looking/fake email sent to user − … that contains a link to a fake website − User clicks link and enters personal details (into fake website) 3 4(b) Any two from: − Pharming − Spyware − Hacking/cracking 2

Cambridge IGCSE Computer Science · 0478

IGCSE Computer Science (0478) The internet and its uses past paper questions

Revise IGCSE Computer Science (0478) — The internet and its uses with real Cambridge past-paper questions grouped by topic, each shown with its marking scheme. Working one topic at a time targets exactly the skill each question tests.

72 free questions from 2016–2021, each with its marking scheme. Open the full topical bank to filter by subtopic, paper, and year.