Year 11 · ICT · Spring 2

Paper 1 theory revision · Lesson 2 of 5

Topics 4 to 6 under time

Exam practice4.2 Network issues and communication5.2 Potential health problems6.8 Expert systems

Year 11 · ICT · Paper 1 theory revision · Lesson 2 of 5

You will learn to

  • Answer a timed Paper 1 section on topics 4 to 6.
  • Describe authentication methods and conferencing, with advantages and disadvantages.
  • Suggest a way to prevent each health problem, linked to its cause.
  • Use the mark scheme to mark your answers and update your tracker.

Year 11 · ICT · Paper 1 theory revision · Lesson 2 of 5

Success criteria

You have got it when you can say:

  • I can finish the section in the time given.
  • I can link each health problem to its cause and one way to prevent it.
  • I can name the five parts of an expert system.

Year 11 · ICT · Paper 1 theory revision · Lesson 2 of 5

Retrieval starter

Questions from before. Write your answers, then show them.

  1. Last lesson

    A digital certificate…

    A Encrypts your hard diskB Blocks pop-upsC Proves a website is who it says it is

    C. Proves a website is who it says it is

  2. Last unit

    Cropping…

    A Cuts away part of the imageB Makes it brighterC Flips it

    A. Cuts away part of the image

  3. Earlier this year

    A format check on a postcode…

    A Checks the postcode existsB Checks the pattern of letters and numbersC Checks only the length

    B. Checks the pattern of letters and numbers

Year 11 · ICT · Paper 1 theory revision · Lesson 2 of 5

Key words (1 of 6)

Network
Two or more devices connected so they can share data and resources.
NIC
Network interface card: hardware that connects a device to a network.
IP address
An address that identifies a device on a network or the internet.
LAN
Local area network: covers one building or site.

Year 11 · ICT · Paper 1 theory revision · Lesson 2 of 5

Key words (2 of 6)

Authentication
Proving a user is who they say they are.
Biometrics
Using unique body features such as fingerprints for authentication.
One-time password
A code that works only once, made by a token.
Zero login
Authentication without typing, using biometrics and behaviour.

Year 11 · ICT · Paper 1 theory revision · Lesson 2 of 5

Key words (3 of 6)

Anti-malware
Software that detects, quarantines and removes malicious software.
Smart device
A microprocessor-controlled device that connects to the internet and can be controlled remotely.
Data security
Protecting personal data from being stolen, changed or misused.
RSI
Repetitive strain injury: pain in fingers, wrists or arms from repeated movements.

Year 11 · ICT · Paper 1 theory revision · Lesson 2 of 5

Key words (4 of 6)

Ergonomic
Designed to fit the human body and reduce strain.
Eye strain
Tired, sore or dry eyes and blurred vision from long screen use.
Anti-glare filter
A screen cover that reduces reflected light.
Posture
The way you hold your body when sitting or standing.

Year 11 · ICT · Paper 1 theory revision · Lesson 2 of 5

Key words (5 of 6)

Computer model
A program that uses rules and formulas to act like a real system.
What if
Changing a model's inputs to see what would happen.
Expert system
Software that copies the knowledge and decisions of a human expert.
Inference engine
The part of an expert system that applies rules to facts to reach conclusions.

Year 11 · ICT · Paper 1 theory revision · Lesson 2 of 5

Key words (6 of 6)

Knowledge base
The store of facts in an expert system.
Rules base
The IF … THEN rules in an expert system.

4.2 Network issues and communication · The explanation · step 1 of 14

Security of data transfer

Data on a network can be intercepted, changed or stolen. Networks also spread malware quickly.

Authentication means proving that a user is who they say they are, before they get access.

Common protections: user IDs and passwords, firewalls, encryption of data being sent, and anti-malware software.

4.2 Network issues and communication · The explanation · step 2 of 14 · part 1 of 3

Strong and weak passwords

A weak password is short or easy to guess: a name, a birthday, a word from the dictionary, `123456` or `password`.

A strong password is long and mixes upper-case letters, lower-case letters, numbers and symbols. It is not a real word and is not linked to the user.

Each extra character multiplies the number of possible passwords. So length matters most. Type passwords into the checker and watch the time to crack change.

4.2 Network issues and communication · The explanation · step 2 of 14 · part 2 of 3

Strong and weak passwords (continued)

e.g.Example
Assume an attacker's computer tries 10 billion guesses a second. 8 lower-case letters: 26^8 = about 209 billion options. Cracked in about 21 seconds. 8 characters from all 95 keyboard characters (including the space): 95^8 = about 6.6 × 10^15. About 8 days. 12 characters from all 95: 95^12 = about 5.4 × 10^23. About 1.7 million years.

4.2 Network issues and communication · The explanation · step 2 of 14 · part 3 of 3

Strong and weak passwords (continued)

!Watch out

A strong password is still unsafe if it is reused on many sites, written on a sticky note, or never changed after a data breach.

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

4.2 Network issues and communication · The explanation · step 3 of 14 · part 1 of 2

Passwords and biometrics

Passwords are the most common method. They are cheap and easy, but can be guessed, forgotten, seen by shoulder surfing or stolen by spyware.

Biometrics use a unique part of a person's body or behaviour: fingerprint, face, iris or retina, voice or handwriting.

4.2 Network issues and communication · The explanation · step 3 of 14 · part 2 of 2

Passwords and biometrics (continued)

BiometricAdvantageDisadvantage
FingerprintQuick and cheap; unique to each personDirty or cut fingers may not be recognised
Face recognitionNo contact neededLighting, glasses, beards or ageing can cause errors
Iris / retina scanVery accurate and very hard to fakeExpensive; retina scanning is intrusive
Voice recognitionWorks over the phone; no extra hardware on a phoneColds and background noise cause errors; can be recorded and replayed
?Why?

Biometrics are more secure than passwords because a body feature cannot be forgotten, shared or easily guessed.

4.2 Network issues and communication · The explanation · step 4 of 14 · part 1 of 3

Cards and tokens

A magnetic stripe card holds data such as a staff ID on its stripe. It is swiped to open doors. Cheap, but easy to copy and damaged by magnets.

A smart card has a chip that stores and processes data, often with an RFID antenna. It is harder to copy and can hold more data. Often used with a PIN.

A physical token is a small device that shows a one-time password (OTP). Some need the user's PIN first. Banks use them for online banking.

4.2 Network issues and communication · The explanation · step 4 of 14 · part 2 of 3

Cards and tokens (continued)

An electronic token is software, usually an app on a phone, that creates a one-time code or approves a log-in. Codes change every 30 to 60 seconds, so a stolen code is soon useless.

e.g.Example
Logging in to online banking: 1. Type user ID and password (something you know). 2. Open the bank's app, which shows a 6-digit code that changes every 30 seconds (something you have). 3. Type the code. Two different factors make it much harder for a hacker.

4.2 Network issues and communication · The explanation · step 4 of 14 · part 3 of 3

Cards and tokens (continued)

!Watch out

A token's code is a one-time password. Say why it helps: even if it is intercepted, it cannot be used again.

4.2 Network issues and communication · The explanation · step 5 of 14

Zero login

Zero login is a way of authenticating without typing anything. The system recognises the user from biometrics and behaviour, such as how they hold the phone, how they type and where they usually are.

Advantage: very convenient, and nothing to forget.

Disadvantage: the system collects lots of personal data, users may not know they are being tracked, and it is harder to tell how secure it is.

4.2 Network issues and communication · The explanation · step 6 of 14 · part 1 of 2

Anti-malware

Malware is software designed to harm a computer or steal data, such as viruses, spyware and ransomware.

Anti-malware software (including anti-virus) scans files and emails, compares them with a database of known malware signatures, and watches for suspicious behaviour.

Infected files are quarantined (isolated so they cannot run) or deleted. The software must be updated regularly so it knows about new malware.

4.2 Network issues and communication · The explanation · step 6 of 14 · part 2 of 2

Anti-malware (continued)

?Why?

On a network, one infected computer can infect all the others, so every device needs up-to-date anti-malware.

The explanation · 8 more steps

More on the lesson page

The lesson page has the rest of the explanation, step by step:

  • Electronic conferencing
  • Why computers can harm health
  • Repetitive strain injury (RSI)
  • Back and neck problems
  • Eye problems and headaches
  • What an expert system is and where it is used
  • The five components
  • Setting up an expert system, and its pros and cons

Open the lesson page

Year 11 · ICT · Paper 1 theory revision · Lesson 2 of 5

Quick quiz · 1 of 3

A touch screen that senses the electricity in your finger is…

  1. A Capacitive
  2. B Resistive
  3. C Infra-red

A. Capacitive

Resistive needs pressure; infra-red uses a grid of beams.

Year 11 · ICT · Paper 1 theory revision · Lesson 2 of 5

Quick quiz · 2 of 3

A 3D printer is…

  1. A An input device
  2. B A storage device
  3. C An output device

C. An output device

It produces something from the computer: output.

Year 11 · ICT · Paper 1 theory revision · Lesson 2 of 5

Quick quiz · 3 of 3

Chip and PIN checks…

  1. A The chip, then the PIN you type
  2. B Your fingerprint
  3. C Only your signature

A. The chip, then the PIN you type

The terminal reads the chip and the PIN confirms it is you.

Year 11 · ICT · Paper 1 theory revision · Lesson 2 of 5

Exit ticket

Answer on paper before you go. Then check.

  1. Magnetic tape is used for…

    A PhonesB Fast game loadingC Large, cheap backups

    C. Large, cheap backups Slow to find things, but huge capacity at low cost.

  2. A Blu-ray disc is…

    A MagneticB Solid stateC Optical

    C. Optical Read by a laser, like CD and DVD.