← VCE Data Analytics U4O2

Integrity as a security evaluation criterion

Judging a security strategy by whether it stops unauthorised people changing or corrupting data, using tamper detection, hashes and checksums, and limits on who can edit.

Part of: VCE Data Analytics - U4O2 - Cyber Security: Data Security — Module 33

Understanding Integrity as a security evaluation criterion in VCE Data Analytics U4O2

What it does: The mismatch between checksums reveals tampering, which is how a strategy detects threats to integrity. Logging each edit is a control that detects tampering and holds users accountable. Integrity is about data staying accurate and unaltered. Keeping data online is the availability criterion. Comparing hashes detects changes but does not block access. It supports integrity by showing that data has been altered. Restricting write access to authorised people reduces the chance of unauthorised or accidental changes. Encryption mainly protects confidentiality. Without edit limits and tamper detection, integrity is still at risk. Backup speed relates to recovery and availability. An integrity measure looks at blocking or detecting unauthorised changes.

Common mistakes: The risk and control describe data being altered and caught by a hash check, so the criterion is integrity. Availability is about whether data can be accessed, so the first line should be criterion = "integrity". The message runs when the two hashes match, which means the file is unchanged. Saying 'tampered' is the wrong conclusion. It should print "File unchanged".

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This module's key terms are also in a printable crossword (Modules 26–43) and word search (Modules 1–43).

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Learning

Duo

When evaluating a security strategy against integrity, which question should you ask?

Does it stop unauthorised people changing or corrupting the data?Does it make sure the data is always online when needed?

Matches

Strategy: all staff can edit the customer database. Integrity criterion: met.

↓

Giving every staff member edit access lets unauthorised people change or corrupt data, so the integrity criterion is not met.

Applying

Meanings

Term

integrity criterion

Meaning

Judging a security strategy by whether it stops unauthorised people changing or corrupting data, using tamper detection, hashes and checksums, and limits on who can edit.

Practice

savedHash <- HASH(report)

Testing

Gaps

digest = hashlib.(data).hexdigest()

Check Answer

Spots

1criterion = "availability"

2risk = "data is altered"

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Quick Questions

1. When evaluating a security strategy against integrity, which question should you ask?

A. Does it stop unauthorised people changing or corrupting the data? ✓

B. Does it make sure the data is always online when needed?

Integrity is about data staying accurate and unaltered. Keeping data online is the availability criterion.

2. A school stores a hash of each exam results file and recalculates it each night. Which integrity feature is this?

A. Tamper detection, because a changed file gives a different hash ✓

B. Access limiting, because it stops students opening the file

Comparing hashes detects changes but does not block access. It supports integrity by showing that data has been altered.

3. Which control best supports integrity by limiting who can edit data?

A. Giving every employee write permission so work is faster

B. Giving only payroll staff write permission to the pay records ✓

Restricting write access to authorised people reduces the chance of unauthorised or accidental changes.

4. A file is downloaded and its checksum does not match the one published by the supplier. What does this suggest?

A. The file has been successfully encrypted

B. The file may have been corrupted or altered ✓

A checksum mismatch means the data is not identical to the original, which is a possible integrity failure.

5. A strategy encrypts all customer data but lets every staff member edit it. How does it rate on the integrity criterion?

A. Weak, because unauthorised edits are still possible ✓

B. Strong, because encryption stops all changes

Encryption mainly protects confidentiality. Without edit limits and tamper detection, integrity is still at risk.

Match the Pairs

SHA-256 hash of file = stored hash → Checking that a file has not been altered, because any change to the data would produce a different hash value

Edit permission: Payroll Officers only → Limiting who can change records so unauthorised users cannot alter or corrupt the data

A checksum lets a system detect that data was corrupted or changed during storage or transfer → IF calculated_checksum != original_checksum THEN flag_file_as_changed

An audit trail supports integrity by recording who changed a record and when, so unauthorised edits can be found → LOG: user=jsmith, action=EDIT, record=4521, time=14:02

Strategy: all staff can edit the customer database. Integrity criterion: met. → Giving every staff member edit access lets unauthorised people change or corrupt data, so the integrity criterion is not met.

Strategy: encrypt files so nobody can read them. Integrity criterion: fully met. → Encryption mainly protects confidentiality. It does not detect tampering or limit who can edit, so integrity is not shown to be met.

Key Term

integrity criterion

Judging a security strategy by whether it stops unauthorised people changing or corrupting data, using tamper detection, hashes and checksums, and limits on who can edit.

Fill in the Blanks

1. digest = hashlib.sha256(data).hexdigest()

Hint: Type the name of the hashing algorithm that creates a fingerprint of the data.

2. if newHash == savedHash: print("Data is unchanged")

Hint: Type the operator that tests whether the new hash is equal to the original hash, which is how tampering is detected.

3. GRANT SELECT ON results TO viewer;

Hint: Type the SQL privilege that lets a user read data but not edit it.

4. REVOKE UPDATE ON results FROM intern;

Hint: Type the SQL privilege that lets someone change existing rows, which is being removed here.

5. IF checksum(file) != storedSum THEN ALERT("Possible tampering") END IF

Hint: Type the name of the function that calculates a small check value from a file to detect changes.

Spot the Error

Question 1

A criterion = "availability"

B risk = "data is altered"

C control = "hash check"

Line A — The risk and control describe data being altered and caught by a hash check, so the criterion is integrity. Availability is about whether data can be accessed, so the first line should be criterion = "integrity".

Question 2

A stored = hash(file)

B later = hash(file)

C if stored == later:

D print("File tampered")

Line D — The message runs when the two hashes match, which means the file is unchanged. Saying 'tampered' is the wrong conclusion. It should print "File unchanged".

Question 3

A editors = ["admin", "hr"]

B if user not in editors:

C allow_edit()

D else: deny_edit()

Line B — Using 'not in' lets only people who are NOT authorised edit the data, which defeats the integrity control. The check should be if user in editors:.

Question 4

A old_hash = "a41f9c"

B new_hash = old_hash

C if new_hash != old_hash:

D alert("Tampering")

Line B — The new hash must be recalculated from the current file. Copying old_hash means the two values always match and tampering is never detected. It should be new_hash = hash(file).

Question 5

A ok = ["admin", "hr"]

B for entry in edit_log:

C if entry.user in ok:

D flag(entry)

Line C — The audit check should flag edits made by people who are NOT authorised. Flagging authorised users gives false alarms and misses real tampering. It should be if entry.user not in ok:.

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