FIT1047 Chap.12 Security Goals, Authentication and Cryptography
Security Goals, Authentication and Cryptography
Security analysis starts with an asset, required property and harmful event. Threats are potential causes; vulnerabilities are exploitable weaknesses; risk reflects likelihood and impact under context; controls reduce risk but leave residual exposure. Confidentiality, integrity and availability are distinct goals that can conflict.
Authentication supports an identity claim, authorisation decides permitted actions and sessions carry identity context forward. Password verification requires salted password-specific derivation, while online rate controls address a different guessing threat.
Cryptographic tools are chosen by property: authenticated encryption for confidential/integrity-protected data, MACs for shared-key authentication, signatures for public verification, hashes for digests under separately trusted references and password KDFs for stored verifiers. Public-key systems depend on authentic key binding and lifecycle.
Access control, least privilege, recovery and monitoring turn primitives into an operational design. Examples are standard canon and do not prescribe the live Project. Security claims should be expressed as mechanisms under assumptions: identify the asset and property, explain how a control changes a threat path, name key or identity dependencies and state residual exposure.
No primitive provides every property, and operational recovery can be as decisive as initial prevention. The published A4 evidence establishes only a Project purpose involving vulnerabilities, attacks and controls for a medium-enterprise context; it does not establish the live scenario, deliverables, rubric, length, collaboration model or required products.
What this chapter covers
- 01
Assets, threats, vulnerabilities and risk
- 02
Confidentiality, integrity and availability
- 03
Authentication, authorisation and sessions
- 04
Multi-factor enrolment and recovery
- 05
Password derivation and online controls
- 06
Symmetric authenticated encryption
- 07
Public keys, certificates and hybrid use
- 08
Hashes, MACs, signatures and access control
- 09
Control mechanisms, dependencies and residual risk
- 10
Credential, key and session lifecycle checks
- 11
Recovery paths as part of security design
AskSia-authored practice weighting (not an official mark scheme): Fresh payroll-export security analysis
- assetName confidentiality, integrity and availability needs plus employee impact.
- threatMap stolen credentials, broad sharing, unauthorised export and ransomware paths.
- controlsChoose strong MFA, role-scoped access, authenticated encryption, export alerts and isolated tested recovery.
- justifyExplain each mechanism and key/identity/owner dependency.
- residualState residual insider/endpoint risk and add minimisation, separation and monitoring.
Key terms
- Asset
- Information, service, identity, device or process whose value or required properties must be protected.
- Threat
- A potential actor or event capable of causing harm.
- Vulnerability
- A weakness that can be exploited or triggered by a relevant threat.
- Authentication
- Evidence supporting a claimed identity under a process.
- Message authentication code
- Shared-secret integrity/authenticity evidence for message data.
- Digital signature
- Private-key-created evidence verifiable with an authentic public key, providing integrity/signer-key evidence rather than secrecy.
- Security mechanism
- The causal way a control changes a threat path, such as preventing an action, detecting it, limiting impact or enabling recovery. Naming a product or primitive is not enough; the mechanism, assumptions and remaining bypasses must be explained.
- Operational dependency
- A service, key, identity process, administrator action or recovery capability that a control needs to remain effective. Dependencies can create shared failure paths, so they belong in the threat and residual-risk analysis.
Security Goals, Authentication and Cryptography FAQ
What is the difference between a threat and vulnerability?
A threat is a possible cause of harm; a vulnerability is the weakness that gives it a path. Risk depends on relevance, likelihood, impact and controls.
Is two passwords multi-factor?
No. Both are knowledge factors. Multi-factor combines independent evidence categories and must secure enrolment and recovery.
Does encryption guarantee integrity?
Not by itself. Use an established authenticated-encryption construction or separate appropriate authentication under a designed protocol.
Why does a plain hash not authenticate a file?
Anyone can recompute it. The comparison is useful only when the reference digest is obtained through a trusted/authenticated source.
Why is key management part of cryptography?
Generation, identity binding, storage, permitted use, rotation, revocation, backup and destruction determine whether the mathematical primitive protects the intended parties.
How should a proposed security control be validated?
Test the property it claims to provide with authorised synthetic data, then test failure, revocation and recovery paths. Configuration presence alone does not prove correct enforcement, usable alerts, protected keys or successful restoration.
What is safely known about FIT1047 A4?
Only the broad Project purpose involving vulnerabilities, attacks and controls for a medium-enterprise context. The live scenario, required artefacts, report structure, collaboration, rubric, length and submission mechanics are not established here and must be confirmed in Moodle.
Assessment move
Use one asset–property–threat–vulnerability–control–residual-risk chain per scenario. Challenge every proposed control with its dependencies and bypass paths. For identity, trace enrolment, authentication, session, sensitive action, recovery and revocation. For password storage, distinguish unique salt/password KDF from online rate limiting and any separately stored server secret.
Build a crypto chooser that maps properties to authenticated encryption, MAC, signature, hash or password KDF; add key ownership and freshness. For access control, write subject/action/object/context decisions, least privilege, separation and review. Test controls operationally with authorised synthetic data—revocation, access review, alert and restore—not merely configuration screenshots.
Verify live Project requirements in Moodle. Use the course-developed textbook for security topic scope and standard definitions, then rewrite every threat chain, key diagram and control analysis independently. Do not copy prose, figures, scenarios or recommended answers. Follow the live A4 brief rather than treating these original headings as a predicted project template.
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