← WA Computer Science ATAR Unit 2

Australian computer offences law

A crime under the Cybercrime Act 2001 (Cwlth) and the WA Criminal Code: accessing, changing or impairing computer data or systems without authorisation. Authorisation is a defence.

Part of: WA Computer Science ATAR Year 11 — Cyber Security — Module 147

Understanding Australian computer offences law in WA Computer Science ATAR Unit 2

What it does: Section 478.1 of the Commonwealth Criminal Code covers unauthorised access to, or modification of, restricted data. Computer offences require the access to be unauthorised, so permission from the owner removes the offence. This is why penetration testers need written authorisation. Impairing means reducing the performance or availability of a system. A DoS or DDoS attack does this without authorisation. Changing records you have no permission to change is unauthorised modification. Editing your own profile where the system allows it is authorised. The Cybercrime Act 2001 is the Commonwealth law that created the federal computer offences. The offences depend on whether access was authorised, not on who the person is.

Common mistakes: Computer offences involve access WITHOUT authorisation. The condition should be IF access AND NOT authorised. The Cybercrime Act 2001 is Commonwealth (Cwlth) law, not WA law. It should be jurisdiction <- 'Cwlth'.

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This module's key terms are also in a printable crossword (Modules 125–266) and word search (Modules 28–266).

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Each concept is reinforced from every angle — learned, then applied, then tested.

Learning

Duo

A student guesses a classmate's password and only reads their emails, changing nothing. Is this a computer offence?

Yes, it is unauthorised access to dataNo, nothing was changed so no offence

Matches

Only outside hackers can commit computer offences

↓

Insiders can also commit computer offences. An employee who accesses or changes data beyond their permission breaks the law.

Applying

Meanings

Term

computer offence

Meaning

A crime under the Cybercrime Act 2001 (Cwlth) and the WA Criminal Code: accessing, changing or impairing computer data or systems without authorisation. Authorisation is a defence.

Practice

IF accessed_data AND NOT authorised THEN

Testing

Gaps

Cybercrime Act 2001 ()

Check Answer

Spots

1// Cybercrime Act 2001 (Cwlth)

2IF access AND authorised

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Quick Questions

1. A student guesses a classmate's password and only reads their emails, changing nothing. Is this a computer offence?

A. No, nothing was changed so no offence

B. Yes, it is unauthorised access to data ✓

Unauthorised access alone can be an offence. The data does not need to be changed or damaged.

2. Which law introduced the main Commonwealth computer offences into the Criminal Code?

A. Copyright Act 1968 (Cwlth)

B. Cybercrime Act 2001 (Cwlth) ✓

The Cybercrime Act 2001 (Cwlth) added computer offences to the Commonwealth Criminal Code. The Copyright Act covers creative works, not computer offences.

3. Which statement about computer offence laws in WA is correct?

A. The Criminal Code (WA) has its own computer offences, alongside the Commonwealth laws ✓

B. Only the Commonwealth has computer offences, so WA law never applies

Both levels of government have computer offences. The Criminal Code (WA) covers computer crime under state law, and the Commonwealth Criminal Code covers it nationally.

4. A hacker floods a school's server so legitimate users cannot reach it. Which type of computer offence is this?

A. Unauthorised impairment of a system ✓

B. Authorised modification of data

Impairing means reducing the performance or availability of a system. A DoS or DDoS attack does this without authorisation.

5. A penetration tester has written authorisation from a company to test its network within an agreed scope. Why is the tester not committing an offence?

A. Authorisation is a defence to unauthorised access ✓

B. Testers are exempt from all computer offence laws

Computer offences depend on the access being unauthorised. Written authorisation and a clear scope are what make the testing lawful. Testers have no blanket exemption.

Match the Pairs

Cybercrime Act 2001 (Cwlth) → Commonwealth law that added computer offences to the Criminal Code Act 1995 (Cwlth), covering unauthorised access, modification and impairment

Criminal Code (WA) s 440A → WA offence for unlawfully operating a computer system, such as using it without permission

Opening restricted data you have no permission to see is a computer offence → s 478.1 unauthorised access to restricted data

Authorisation is a defence: access with the owner's permission is not an offence → IF access_authorised THEN no offence

Only outside hackers can commit computer offences → Insiders can also commit computer offences. An employee who accesses or changes data beyond their permission breaks the law.

Looking at data is legal as long as you change nothing → Unauthorised access alone can be an offence. Modifying or impairing data is not required.

Key Term

computer offence

A crime under the Cybercrime Act 2001 (Cwlth) and the WA Criminal Code: accessing, changing or impairing computer data or systems without authorisation. Authorisation is a defence.

Fill in the Blanks

1. Cybercrime Act 2001 (Cwlth)

Hint: Type the abbreviation showing this is a federal (Commonwealth) law.

2. Access without authorisation is an offence

Hint: Type the word for official permission to use a system, which is missing in this offence.

3. Unauthorised modification of data is a crime

Hint: Type the word for changing or altering stored data.

4. Criminal Code (WA) covers computer offences

Hint: Type the abbreviation for our state, whose Criminal Code also has computer offences.

5. Authorisation is a defence to the offence

Hint: Type the legal word for a reason that can stop a person being found guilty.

Spot the Error

Question 1

A // Cybercrime Act 2001 (Cwlth)

B IF access AND authorised

C offence <- TRUE

D ENDIF

Line B — Computer offences involve access WITHOUT authorisation. The condition should be IF access AND NOT authorised.

Question 2

A law <- 'Cybercrime Act 2001'

B jurisdiction <- 'WA'

C OUTPUT law, jurisdiction

Line B — The Cybercrime Act 2001 is Commonwealth (Cwlth) law, not WA law. It should be jurisdiction <- 'Cwlth'.

Question 3

A IF data_changed THEN

B IF NOT authorised

C offence <- TRUE

D ENDIF

E ENDIF

Line B — The IF statement is missing THEN, so the pseudocode is syntactically wrong. It should be IF NOT authorised THEN.

Question 4

A IF impair AND allowed THEN

B offence <- TRUE

C ELSE

D offence <- FALSE

Line A — Impairing a system is an offence only when it is NOT authorised. Authorised impairment, such as an admin shutting down a server, is not an offence. It should be IF impair AND NOT allowed THEN.

Question 5

A act <- 'Cybercrime Act 2001'

B level <- 'Commonwealth'

C defence <- 'curiosity'

D OUTPUT act, level, defence

Line C — Curiosity is not a defence to a computer offence. The defence is authorisation, so it should be defence <- 'authorisation'.

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