Cambridge A Level Information Technology (from 2017) 9626 — 2018 Oct/Nov Paper 3 · Variant 2

1 Credit card accounts are often required for payment when buying goods online. (a) Describe how the use of a credit card for online purchases may subject credit card account holders to fraud. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...............................................................................................................................................[8] (b) Explain how a merchant selling goods online can attempt to combat credit card fraud. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...............................................................................................................................................[5]

Mark scheme: Question Answer Marks 1(a) Eight from: 8 (Unauthorised persons obtain credit card details by various methods): skimming/interception of details/theft of details from website/phishing Use of number generator to create card numbers close to known good one Last four numbers are usually in a sequential range with same expiry date Use of generated card numbers to make transactions Even if customer not present/if card stolen transactions can still be carried out using security numbers Security number obtained by theft/phishing/selling/smishing by unscrupulous merchants Thieves/hacker use credit card for small transaction to see if valid Once small transaction is successful then much larger transactions are made Subscriptions to web services are a common method to test card validity as nothing physical is purchased Repeat billing/invoicing/recurring charges for card holder An uncancelled ‘membership’ is charged monthly Use of spyware/keylogger software to capture credit card numbers/details as they are typed. 1(b) Five from: 5 Demand for extra security information/PIN or card security code/last three numbers Check location of card holder matches address given for delivery by use of IP lookup of purchaser for geolocation Compare delivery address with credit card billing address Use of third-party services/escrow services to take payment from card account and pass it to merchant Not displaying the full card number (Primary Account Number – PAN truncation) on receipts/email/website confirmations Not storing the whole number/credit card details on computer systems Encrypt stored credit card details so that they are not understood by unauthorised persons.

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2 Some text is being written for use as a title in a slideshow presentation. The text is to be zoomed in and out as the titles are displayed in different sizes on the slides. The sample letter in Fig. 1 has been created as a bitmap graphic while the sample letter in Fig. 2 has been created as a vector graphic. B B Fig. 1 Fig. 2 B Explain, in detail, why letters created as in Fig. 2 are more suitable for use in the slideshow than those created as in Fig. 1. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[6]

Mark scheme: 2 Six from: 6 Fig. 2 can be scaled/zoomed without loss of quality/clarity Because it is (a vector graphic) made up of instructions/code on how to create the letter When resized/zoomed the graphic is recalculated so no loss of quality Fig. 1 cannot be scaled/zoomed without loss of quality/clarity Because it is (a bitmap image) made of square pixels The rounded appearance is created by pixels of varying density If zoomed/enlarged too much then pixels are visible If zoomed the letter becomes blurred/lacks definition/unreadable.

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3 Evaluate the impact on the environment of the use of robotics in industry. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[8]

Mark scheme: 3 This question to be marked as a Level of Response. 8 Level 3 (7–8 marks) Candidates will evaluate in detail the impact of the use of robots on the environment. The information will be relevant, clear, organised and presented in a structured and coherent format. There will be a reasoned conclusion/opinion. Subject specific terminology will be used accurately and appropriately. Level 2 (4–6 marks) Candidates will explain the impact of the use of robots on the environment. For the most part, the information will be relevant and presented in a structured and coherent format. There may be a reasoned conclusion/opinion. Subject specific terminology will be used appropriately and for the most part correctly. Level 1 (1–3 marks) Candidates will describe the impact of the use of robots on the environment. Answers may be in the form of a list. There will be little or no use of specialist terms. Level 0 (zero marks) Response with no valid content. Answers may make reference to e.g.: More selective/accurate spraying of crops thus diminishing overspray/use of chemicals on crops Remote monitoring of global warming/oil spills/water pollution with use of independent robotic submarines carrying sensors into dangerous areas Autonomous gathering of data in dangerous/hazardous areas to monitor environmental factors Use in food packaging/production by reduction in contamination of product as no human contact Use in industry to reduce environmental waste/resource use... ...e.g. solar panel cleaning robot uses less water than humans ...less energy used in ‘dark’ factories where heating and lighting are not so important as few humans work in them Leads to reduction in traffic so there is less pollution Negative impacts could include: ...increased use of power over manual labour ...increased use of scarce resources e.g. precious/rare metals to manufacture robots ...environmental damage caused by extraction of precious/rare metals.

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4 Fig. 3 shows a diagram of interconnected computer networks that use internet protocol (IP) and packet switching to communicate. A large file is sent from network A to network H. Nodes B to G are routers used to connect the networks. During the sending of the file from network A, network I also starts to send a much larger video file to network H. C E File sent File from A being from A received at H A B G H File from I being received at H File sent from I I D F Fig. 3 (a) Explain, in detail with reference to the diagram, how the file from network A and the file from network I travel through the network from router to router and start to arrive at network H at the same time. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...............................................................................................................................................[6] (b) Explain why router C does not always send the packets to router D. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...............................................................................................................................................[6]

Mark scheme: 4(a) Six from: 6 Each packet sent by network A takes a different route through the network Each packet has source/destination address stored in header Each router has a stored lookup table of IP addresses/routes to the destination (if known) Routing table is stored at control plane of router Used to choose next router/router to send packet to Static routes are pre-programmed to show route to destination B to C to E to G Dynamic routing protocols build up table of preferred routes between connected networks B to C to F to G if router E is inefficient/out of action/in heavy demand If destination is unknown router B will send packet to next known router, C or D If C/D router does not know destination to H then packet is sent onto next router, E or F. 4(b) Six from: 6 Router D may be not responding Router D may be in heavy demand Router D may have failed/be offline There may a policy set up in router C to over-ride the routing tables so that the packets are not sent to router D To enforce a QoS for specific services that take precedence over other packets Router C may have more than one set of routing protocols because it is connecting to several different networks at once Alternative routers may respond quicker/before router D/alternative routes are available sooner than via router D.

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5 Quintin is a programmer who writes code in HTML and JavaScript for use in online forms. The code is developed and ‘white-box’ tested before being used. Quintin is developing the code below. He has added comments to the code. The code asks a user to input two numbers and adds the numbers together. It also displays the total and whether or not it is greater than 10. <html> <body> <!-- the next six lines collect the two numbers to be added--> <br/>Enter first number: <input type="number" id="nm1" name="num1"> <br/><br/>Enter second number: <input type="number" id="nm2" name="num2"> <p id="add"></p> <script> function myaddfunction() { //the next line assigns the first number input to the variable y var y = document.getElementById("nm1").value; //the next line assigns the second number input to the variable z var z = document.getElementById("nm2").value; //the next line adds the two numbers and assigns the result to the variable x var x = +y + +z; //the next line checks if x is greater or not greater than 10 and reports accordingly var A = (x >10) ? x+ " is greater than 10":x+ " is not greater than 10"; //the next line prints the results onto the page document.getElementById("add").innerHTML = A ; } </script> <!-- the next two lines asks the user to click the button and then the script is executed <p>Click the button to calculate the total.</p> <button onclick="myaddfunction()">Add the numbers</button> <br/> </body> </html> (a) Explain how Quintin could use ‘white box’ testing to ensure that the JavaScript code produces the correct result every time. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... 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................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...............................................................................................................................................[8] (b) Explain why it is good practice that Quintin places his JavaScript code in external files rather than embeds the code in the actual page code. ................................................................................................................................................... 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Mark scheme: 5(a) Eight from: 8 Checking each line of code/statement Ensures that each line of code is executed at least once Ensures that var y and z assign the collected numbers as required Checks that the additon of y and z is correct Ensures that the correct message is displayed when result assigned to A Checking each branch/decision in the code Checks that decisions are carried out correctly So that values put in A can be compared Ensures that result is checked against > 10 Ensures that the correct result is put in var × as required Checks every possible pathway through the code So that test values in var y and z cause each subsequent path to be followed So that test values in x are assigned to A to produce both the messages “is greater than 10” and “is not greater than 10” depending on value in A. 5(b) Six from: 6 Can separate code into different conceptual/functional areas for ease of development/testing/understanding Separating HTML and JavaScript code provides modularity to code Which is easier to read/maintain/update by Quintin/different coders as required Can call the code several times/from different pages/re-use the code No need to rewrite/have several copies/copies on each web page Code only has to be tested once/checked for errors once File/JavaScript is cached by web browser No need to reload it/fetch code repeatedly if need on other pages Reduces network access/reduces cost of fetching data JavaScript code embedded in web pages can slow loading times/reduce browser performance Web page can slow/stop while browser executes code.

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6 Describe how quantum cryptography can help to ensure that data is kept secure when being transferred electronically between users. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[6]

Mark scheme: 6 Six from: 6 Use of polarised light for encoding data In quantum states for transmission between two parties Initial polarisation/oscillation of first two photons determines 0 and 1 bit of the data Polarisation of subsequent bits is determined at random Recipient measures data using random polarisation until data is as sent Used to establish a shared key between sender/recipients No third party learns/sees the key Key then used to create other keys for use in encryption Called quantum key distribution (QKD) Data state is changed when viewing by others Impossible to copy/eavesdrop on data encoded in quantum state without alerting the sender/recipients.

7 The table shows part of a database used to control the level of stock items in a clothing store. Reordering is done when the number left in stock reaches or falls below the minimum level allowed by the store management. Item_Code Description_of_Item Item_Price Current_Stock_ Minimum_Stock_ Quantity_to-be_ Level Level_Allowed Reordered XYP234 Walking boots (pair) $128.50 16 15 10 ABG765 Jackets $99.56 15 10 15 SCC653 Gloves (pair) $36.99 23 20 25 SOX785 Socks (pair) $25.99 33 30 50 XYT981 Scarf $34.45 16 10 20 A customer purchases two pairs of walking boots, three pairs of socks and a scarf. The items each have a barcode and are scanned at the checkout when purchased. Describe, in detail, the processes that would occur when the purchases have been made to ensure that the appropriate new orders are placed to maintain the stock levels. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[8]

Mark scheme: 7 Eight from: 8 Scanned barcodes contain item code for walking boots/XYP234 Code for walking boots/XYP234 used to look up the items in the database Matching record is found in database 2 pairs of boots sold so value in field holding the number of w/boots in stock is reduced from 16 to 14 ....new value is less than/below/< re-order level/15 so an order for 10 pairs of boots is generated/alert is generated to request an order be placed for 10 pairs 3 pairs of socks have been sold so value in field holding the number of socks in stock is reduced from 33 to 30 Current Stock level is compared with Minimum Stock level allowed ....new value is equal to re-order level so an order for 50 pairs is generated/alert is generated to request an order be placed for 50 pairs Number of scarf/scarves sold is deducted from the value in the field holding the number of scarf/scarves in stock... 1 scarf has been sold so value in field is reduced from 16 to 15... ...new value is above/greater than/ > the re-order level so no order is generated/alert made Re-orders are generated/alerts created to advise staff to (re-)order 10 pairs of walking boots and 50 pairs of socks Automatic orders are placed for the items/staff respond to alerts and place orders for new stock.

8 Evaluate the use of the infra-red method of data transmission in wireless communications. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[8]

Mark scheme: 8 Eight from: 8 Suitable for use in ‘free-space’ i.e. no physical connection medium such as cable or fibre Infra-red LEDs allow point-to-point optical commnciations Infra-red LEDs allow high data rates using laser technology Infra-red LEDs allow relatively inexpensive compared to other radio technologies Uses pulsing modulation/on-off signals which can restrict rates to low data rates in free space Suitable for short distance communication between devices (usually only maximum of a few metres) May not work relaibly when too close together Line of sight required so objects block the signals Not subject to interference as much as other radio technologies Has low power requirements so suitable for use in small/mobile devices/remote controls Can be more secure than other radio technologies as range is low/easily blocked by objects. Max six for all positives or all negatives. 1 mark available for a resoned conclusion/opinion.

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9 A software development company uses throw away prototyping to develop parts of a new system. (a) Give one reason why the company would use throw away prototyping. ................................................................................................................................................... ................................................................................................................................................... ...............................................................................................................................................[1] (b) Describe two drawbacks to the company of using throw away prototyping. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ...............................................................................................................................................[2]

Mark scheme: 9(a) One from: 1 To ensure that the system requirements are valid To ensure that the system requirements are understood by all (Can be) quickest method of obtaining feedback from users about (proposed) main features. 9(b) Two from: 2 Developers can be pressured into delivering unfinished product Prototype may not work well enough so final product is never made/produced/required The time spent on the prototype is lost/cannot be used in development of final product.

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10 Analyse the suitability of using pilot implementation to install and use WiFi internet access for guests in a chain of hotels. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[6] Please turn over for Question 11.

Mark scheme: 10 Six from: 6 Running in one hotel until it is working perfectly When working perfectly it can be installed in the other hotels The method is more effective than installing in all hotels and discovering problems If it does not work only one hotel is affected not the whole chain of hotels Staff at the hotel can be used to train staff at the other hotels Feedback is collected and collating reviews by guests/users in one hotel Will take longer to fully implement all guest access to Wi-Fi in all hotels compared to direct changeover.

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11 Analyse the effectiveness of observation as a research technique. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ......................................................................................................................................................[6]

Mark scheme: 11 Six from: 6 Observation is primary research so is valid/reliable Observer can check the accuracy of the data themselves Observation can be applied to almost any scenario where no verbal responses are possible/obtainable Observation does not require agreement of participants so no need for observer to ask People being observed do not have to give up time to answer questions/give data Observation is not effective for uncertain events as event may take place when observer not present/blinks Some events/phenomena cannot be observed... ...feelings/emotions are not observable so observation is ineffective Observation is unreliable for social phenomena as bias by observer is difficult to remove/compensate for Observers need to have the technical knowledge of what they are observing to be able to make valid observations of a process Observation can be a slow method of research Observation results are difficult to validate.

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