Year 11 · ICT · Spring 2 · Paper 1 theory revision

Topics 7 to 10 under time

Exam practicePresent ▶

What this lesson covers

7.1 Analysis

Cambridge IGCSE ICT 0417 · Topic 7: The systems life cycle · Paper 1

7.4 Implementation

Cambridge IGCSE ICT 0417 · Topic 7: The systems life cycle · Paper 1

8.3 Security of data

Cambridge IGCSE ICT 0417 · Topic 8: Safety and security · Paper 1

You will learn to

Answer a timed Paper 1 section on topics 7 to 10.
Compare the four implementation methods, and choose one for a given scenario.
Compare the four research methods used in analysis.
Use the mark scheme to mark your answers and update your tracker.

Success criteria

I can finish the section in the time given.
I can justify the best implementation method for a scenario.
I can give a matched advantage and disadvantage for each research method.

The syllabus points for these sections

Describe observation, interviews, questionnaires and examining documents.
Give advantages and disadvantages of each research method.
Identify inputs, outputs, processing and problems of the current system.
Identify user requirements and information requirements.
Write a system specification for hardware and software.
Describe direct changeover, parallel running, pilot running and phased implementation.
Give advantages and disadvantages of each method.
Choose the most suitable method for a given scenario and justify it.
Describe hacking, phishing, pharming, smishing, vishing, viruses and malware.
Describe card fraud: shoulder surfing, card cloning and key logging.
Explain how each threat can be prevented.
Describe biometrics, digital certificates, SSL, encryption, firewalls, two-factor authentication, user ID and password.

Key words

Say each word, then read what it means. Every one is in the glossary too.

Systems life cycle: The stages used to create a new system: analysis, design, development and testing, implementation, documentation, evaluation.
Systems analyst: The person who studies the current system and plans the new one.
Questionnaire: A set of written questions given to many people to collect their views.
System specification: A list of the hardware and software the new system needs.
Check digit: An extra digit calculated from the other digits, used to detect input errors.
Data capture form: A paper or on-screen form used to collect data.
Test plan: A table listing each test, its data, the expected and actual outcomes and any remedial action.
Live data: Real data from the organisation, used to test the system with known results.
Direct changeover: The old system stops and the new one starts immediately.
Parallel running: Old and new systems run together until the new one is trusted.
Pilot running: The new system is tried in one branch before the rest.
Phased implementation: The new system is introduced one part at a time across the organisation.
Evaluation: Judging the finished system against the original requirements after it has been used.
Data protection act: A law controlling how organisations collect, store and use personal data.
Sensitive personal data: Personal data, such as health or religion, that could cause harm or unfair treatment if leaked.
Hacking: Getting into a computer system without permission.
Phishing: A fake email with a link to a fake website that steals personal details.
Smishing: Phishing using SMS text messages.
Vishing: Phishing using voice calls or voicemail.
Pharming: Malicious code that redirects a user to a fake website even when the correct address is typed.
Malware: Any software written to cause harm, such as viruses, worms, spyware or ransomware.
Shoulder surfing: Watching someone enter a PIN or password to steal it.
Card cloning: Copying the magnetic stripe of a card to make a fake copy.
Key logging: Recording every key a user presses to steal passwords and card numbers.
Biometrics: Identifying a person by a unique body feature such as a fingerprint or face.
Digital certificate: An electronic document from a trusted authority that proves a website is genuine.
SSL: A protocol that encrypts data between a browser and a web server; shown by https and a padlock.
Encryption: Scrambling data with a key so only someone with the right key can read it.
Firewall: Hardware or software that checks incoming and outgoing traffic and blocks what breaks set rules.
Two-factor authentication: Logging in with two different types of proof, such as a password and a code sent to a phone.

The explanation

Read it here, or open the study page below to go one step at a time with things to try.

7.1 Analysis

What a system is and why there is a life cycle

A system is a way of doing a job: the people, the data, the steps and the equipment.

The systems life cycle is the order of stages used to build a new system. Each stage feeds the next.

The stages are: analysis, design, development and testing, implementation, documentation, evaluation.

A systems analyst is the person who studies the old system and plans the new one.

e.g.Example

A school library uses paper cards to record loans. Books go missing and nobody knows who has them. The head asks a systems analyst to build a computer system for loans.

?Why?

Working in stages means problems are found early, when they are cheap to fix. A mistake found after the system is live costs far more.

Research method 1 and 2: observation and interviews

Observation means watching people use the current system.

Interviews mean asking people questions face to face, one at a time.

Both methods help the analyst understand the current system before designing a new one.

Method	Advantages	Disadvantages
Observation	The analyst sees what really happens, not what people say happens. Reliable first-hand data. Fairly cheap: only the analyst's time.	People may work differently because they know they are watched (the Hawthorne effect). It can take a long time. Some tasks are not seen if they happen rarely.
Interviews	Questions can be changed during the interview to follow up answers. The analyst can see body language. People can explain problems in detail.	Very time-consuming, so only a few people can be interviewed. Expensive (analyst and staff away from work). People may give answers they think the analyst wants. Not anonymous.

e.g.Example

Library example: Observation: the analyst sits at the desk for a morning and watches loans being written on cards. Interview: the analyst asks the head librarian what goes wrong most often.

Research method 3 and 4: questionnaires and examining documents

A questionnaire is a set of written questions given to many people, on paper or online.

Examining documents means reading the papers and files the current system uses: forms, invoices, reports.

Analysts usually use more than one method, so the weaknesses of one are covered by another.

Method	Advantages	Disadvantages
Questionnaires	Reach many people quickly and cheaply. Can be anonymous, so answers are more honest. People answer when it suits them. Answers are easy to analyse, especially tick boxes.	Many people do not return them. Questions cannot be explained or changed. People may misunderstand a question. Tick boxes limit the answers people can give.
Examining documents	Shows exactly what data the system holds and the format it uses. Helps decide inputs and outputs. Does not interrupt staff.	Very time-consuming to read everything. Documents may be out of date or hard to understand. Costly, because of the analyst's time.

e.g.Example

Library example: Questionnaire: 600 students answer 8 tick-box questions online about how they borrow books. Examining documents: the analyst reads the loan cards and the overdue-letter template.

!Watch out

In exam answers, give an advantage and a disadvantage that fit the scenario. 'It is quick' alone rarely earns a mark. Say quick compared with what, for example 'quicker than interviewing 600 students one by one'.

What the analysis must find out

The analyst records the inputs (data going in), processing (what is done to the data) and outputs (results coming out) of the current system.

The analyst also lists the problems with the current system.

From this come the user requirements (what the users need the system to do) and the information requirements (what information the system must produce).

Finally the analyst writes a system specification: the hardware and software the new system needs.

Item	Library example
Inputs	Student ID, book ISBN, date of loan
Processing	Work out the return date, check if a book is overdue
Outputs	Loan receipt, list of overdue books, reminder emails
Problems	Cards get lost, overdue books are not chased
User requirement	A librarian can record a loan in under 30 seconds
Information requirement	A weekly report of overdue books by tutor group
Hardware specification	PC, barcode reader, receipt printer
Software specification	Database software, operating system, email software

?Why?

The hardware and software choices depend on the requirements. For example, scanning book barcodes needs a barcode reader, and storing thousands of records needs enough storage.

7.4 Implementation

Four ways to change over

Implementation means putting the new system into use. Staff are trained and data from the old system is transferred.

Direct changeover: the old system stops and the new one starts at once, for example over a weekend.

Parallel running: the old and new systems both run at the same time, until the new one is trusted.

Pilot running: the new system is used in one branch or department first. Once it works, it goes to the rest.

Phased implementation: the new system is brought in one part at a time, across the whole organisation.

e.g.Example

A chain of 40 supermarkets gets a new till system. Direct: all 40 shops switch on Monday morning. Parallel: every shop runs old and new tills side by side for a month. Pilot: one shop in Getafe uses it first, then the other 39. Phased: all shops get the new payments part first, then stock control a month later.

!Watch out

Pilot and phased are easy to mix up. Pilot = one place, whole system. Phased = whole organisation, one part at a time.

Advantages and disadvantages

Each method trades cost and speed against risk.

The key question: what happens if the new system fails?

Method	Advantages	Disadvantages
Direct	Cheapest: only one system runs and staff do the work once. Benefits are immediate. Fastest.	Highest risk: if the new system fails, there is no backup and work stops. Data could be lost. Staff must be fully trained before the switch.
Parallel	Lowest risk: if the new system fails, the old one is still working. Results can be compared to check the new system.	Most expensive: staff do every job twice, so extra staff or overtime are needed. Takes longest. Data entered twice can lead to errors.
Pilot	If it fails, only one branch is affected. Staff in the pilot branch can train others. Cheaper than parallel.	Slow to reach the whole organisation. If the pilot branch fails, it suffers on its own. The pilot branch may not be typical of the others.
Phased	If one part fails, only that part is affected and it can be fixed. Staff learn one part at a time.	Slow: takes a long time to fully implement. Parts of old and new systems must work together, which is hard. Costly to evaluate each phase.

?Why?

There is no best method. The right one depends on how bad a failure would be, how much money there is, and whether the system can be split into branches or parts.

Choosing the right method

Use direct when the system is small, simple, or the old system has already stopped working. Also when two systems cannot run side by side.

Use parallel when failure would be serious, such as payroll, banking or hospital records.

Use pilot when the organisation has many similar branches, such as shops or banks.

Use phased when the system splits into separate parts, such as a school system with attendance, marks and timetable modules.

e.g.Example

Try the toy. For each scenario, pick a method and read why. Scenario: a hospital moves patient records to a new system. Best answer: parallel running. A failure could put patients at risk, so the old system must keep working until the new one is proven.

!Watch out

In a 'choose and justify' question, the justification must link to the scenario. 'Parallel is safest' is weak. 'Parallel, because if the new payroll fails, 300 staff still get paid by the old system' is strong.

There is something to try for this step in the IGCSE library.

8.3 Security of data

Hacking

Hacking is getting into a computer system without permission.

A hacker may steal data, delete or change data, or lock the system. This can lead to identity theft or fraud.

Prevention: firewalls, strong passwords and user IDs, two-factor authentication, keeping software up to date, and encryption so stolen data is unreadable.

!Watch out

Encryption does not stop hacking. It stops the hacker understanding the data they steal. Say this clearly in exam answers.

Phishing, smishing and vishing

Phishing: a fake email that looks like it is from a real company, such as a bank. A link takes the user to a fake website that steals their login or card details.

Smishing (SMS phishing): the same trick by text message. Example: 'Correos: your parcel is held, pay 1.99 EUR at this link.'

Vishing (voice phishing): the same trick by phone call or voicemail. The caller pretends to be the bank or the police.

Prevention: do not click links in unexpected messages; type the company's address yourself; check the sender's address; never give passwords or PINs by phone; use spam filters; report it.

e.g.Example

Try the toy. In the bank email, look for the red flags: The sender address is not the bank's own (security@n0rthgate-bank-alerts.net). It says 'Dear Valued Customer', not your name. It creates urgency: 'your account will be closed in 24 hours'. The link goes to a different website, not the bank's. It asks for a PIN and full card number, which banks never do. The School IT email also has a spelling mistake: 'Departmnet'.

?Why?

These attacks trick people, not computers. Spotting the red flags is the best defence, because the message itself contains no virus.

There is something to try for this step in the IGCSE library.

Pharming

Pharming: malicious code is installed on the user's computer or on a DNS server. It sends the user to a fake website even when they type the correct address.

The fake site looks real and collects login and bank details.

Prevention: anti-malware software that scans for pharming code; check the web address and the padlock (HTTPS) before typing details; check the website's digital certificate; do not open unknown attachments.

	Phishing	Pharming
How the user reaches the fake site	Clicks a link in an email	Types the correct address but is redirected
Needs the user to act	Yes, must click the link	No action needed after the code is installed
Where the trick is	In the message	In code on the computer or DNS server

!Watch out

The key difference: in phishing the user clicks a link; in pharming the user types the real address and is still sent to the fake site.

Viruses and other malware

Malware means malicious software: any program written to cause harm.

A virus is a program that copies itself and attaches to other files. It can delete or damage data and make the computer crash or run slowly.

Other malware: worms spread across networks on their own. Trojan horses pretend to be useful software. Spyware secretly records what the user does.

Ransomware encrypts files and demands payment to unlock them. Adware shows unwanted adverts.

Prevention: anti-virus/anti-malware software, kept up to date, with regular scans. Do not open unknown attachments or download from untrusted sites. Keep backups so data can be restored.

?Why?

Anti-virus works by comparing files with a list of known viruses. New viruses appear every day, so an out-of-date list misses them.

Card fraud: shoulder surfing, card cloning and key logging

Card fraud means stealing card details to use someone else's money.

Shoulder surfing: watching someone type their PIN at an ATM or shop, either by looking over their shoulder, using binoculars or a hidden camera.

Card cloning (skimming): a device fitted over an ATM card slot copies the magnetic stripe. The criminal writes the data onto a blank card. Chip and contactless cards are harder to clone.

Key logging: software or a small device records every key pressed, including passwords and card numbers, and sends them to the criminal.

Threat	Prevention
Shoulder surfing	Cover the keypad with your hand. Stand close to the ATM. Use contactless or mobile payment so no PIN is typed. Be aware of who is around.
Card cloning	Check the ATM for loose or odd parts on the card slot. Use chip and PIN or contactless rather than the stripe. Check bank statements regularly.
Key logging	Anti-spyware software. Use drop-down menus or on-screen keyboards to enter parts of a password. Two-factor authentication. Change passwords often.

e.g.Example

Some banks ask for '3rd, 5th and 8th characters of your password' chosen from drop-down boxes. A key logger records no key presses, so it captures nothing useful.

Protection 1: user ID, password and two-factor authentication

A user ID says who you are. A password proves it. Only someone who knows both can log in.

A strong password is long (at least 8 characters, better 12+) and mixes upper case, lower case, digits and symbols. It is not a real word or your name or birthday.

Two-factor authentication (2FA) asks for two different types of proof: something you know (a password) and something you have (your phone) or are (a fingerprint).

Example: you type your password, then the bank sends a 6-digit code to your phone. A thief with only your password cannot log in.

?Why?

Passwords can be guessed, stolen by key loggers or phished. 2FA means a stolen password alone is not enough.

!Watch out

A password plus a security question is not 2FA. Both are 'something you know'.

Protection 2: biometrics

Biometrics identify a person by a unique body feature: fingerprint, face, iris or retina, voice or hand shape.

The feature is scanned and compared with a stored copy.

Advantages	Disadvantages
Cannot be forgotten, unlike a password	Expensive equipment
Very hard to copy or share	Can fail: a cut finger, a cold changes your voice, poor light for face scans
Fast to use, no typing	Privacy worries: stored body data is sensitive data
Unique to each person	If biometric data is stolen, you cannot change your fingerprint like a password

Protection 3: encryption, SSL and digital certificates

Encryption scrambles data using a key, so only someone with the right key can read it. Stolen encrypted data is useless to a thief.

SSL (Secure Sockets Layer) is a protocol (a set of rules) that encrypts data sent between a web browser and a web server. Today its newer version, TLS, does the same job.

When a site uses SSL, the address starts https:// and the browser shows a padlock.

A digital certificate is an electronic document that proves a website is who it says it is. It is issued by a trusted certificate authority and contains the owner's name, the public key, the issuer, a serial number and an expiry date.

e.g.Example

Paying for train tickets on renfe.com: 1. The browser asks the server for its digital certificate. 2. The browser checks the certificate is valid and issued by a trusted authority. 3. Browser and server agree an encryption key (the SSL/TLS handshake). 4. Card details are sent encrypted. A hacker who intercepts them sees only scrambled data.

?Why?

Encryption protects the data on the way. The certificate makes sure you are sending it to the real company, not a fake one.

Protection 4: firewalls

A firewall is software or hardware that sits between a computer (or network) and the internet. It checks all data coming in and going out.

It blocks traffic that does not meet set rules, such as data from blocked addresses or unknown programs trying to connect.

It can log traffic, warn the user about suspicious activity and block access to certain websites.

A firewall does not stop a user who chooses to open an infected attachment, and it does not remove viruses already on the computer.

!Watch out

A firewall is not anti-virus. A firewall controls traffic; anti-virus finds and removes infected files.

Putting it together: threat and protection

Each protection blocks a particular route. Match the protection to how the threat works.

Exam questions often describe a scenario and ask for the threat and the best protection. Ask two things: how did the criminal get in or trick the user? Which protection blocks exactly that route?

Threat	Best protection
Hacking	Firewall, strong passwords, 2FA, encryption (to make stolen data unreadable)
Phishing / smishing / vishing	Do not click links or give details; spam filters; check sender
Pharming	Anti-malware; check the URL, padlock and digital certificate
Viruses and malware	Up-to-date anti-virus/anti-malware; no unknown attachments; backups
Shoulder surfing	Cover the keypad; contactless payment
Card cloning	Chip and PIN or contactless; check the ATM; check statements
Key logging	Anti-spyware; drop-down password entry; 2FA

e.g.Example

Try the toy with each scenario. Scenario: 'Ana typed www.mybank.es correctly but the page asked for her full PIN.' Threat: pharming (correct address, still redirected). Defence: anti-malware to remove the redirect code; check the address, padlock and digital certificate.

There is something to try for this step in the IGCSE library.

Study it

Open the study page and go one step at a time.

ICT topic 1

Check yourself

One question at a time. The reason shows after each answer.

Saved on this device.

Topics 7 to 10 under time

What this lesson covers

You will learn to

Success criteria

Key words

The explanation

What a system is and why there is a life cycle

Research method 1 and 2: observation and interviews

Research method 3 and 4: questionnaires and examining documents

What the analysis must find out

Four ways to change over

Advantages and disadvantages

Choosing the right method

Hacking

Phishing, smishing and vishing

Pharming

Viruses and other malware

Card fraud: shoulder surfing, card cloning and key logging

Protection 1: user ID, password and two-factor authentication

Protection 2: biometrics

Protection 3: encryption, SSL and digital certificates

Protection 4: firewalls

Putting it together: threat and protection

Study it

Types and components of computer systems

Input and output devices

Storage devices and media

Networks and the effects of using them

The effects of using IT

ICT applications

The systems life cycle

Safety and security

Audience

Communication

Algorithms

Cybersecurity

The web

Check yourself