hardMultiple Select
CISSP Practice Question: Which TWO of the following are valid data…
Which TWO of the following are valid data de-identification techniques?
⚠ Common exam trap
Candidates often confuse encryption with de-identification. While encryption protects data confidentiality, it is a cryptographic control that is easily reversed with a key and does not structurally de-identify the dataset for general use. De-identification techniques like masking and tokenization are specifically designed to remove or replace direct and indirect identifiers so that the data can be used or processed with reduced privacy risk.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Data masking
Data masking (C) is a valid de-identification technique because it replaces sensitive values with fictitious but structurally similar data (for example, showing only the last four digits of a credit card), so the original information cannot be reconstructed from the masked output. Tokenization (E) is also valid because it substitutes a sensitive value with a non-sensitive surrogate token that maps back to the original only through a securely stored token vault, removing the sensitive data from the exposed system. Encryption (A) is not de-identification here because it is a reversible confidentiality control that preserves the original data and can be decrypted with the key. Access control (B) restricts who may view data but does not alter or remove the identifying content itself. Backup (D) is a data availability and recovery measure, not a technique for de-identifying data.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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Encryption
Why it's wrong here
Encryption transforms data into an unreadable format using an algorithm and a key. While it protects data confidentiality by making it unintelligible to unauthorized parties, it is inherently reversible. With the correct decryption key, the original identifiable data can be fully restored, meaning it does not permanently remove the link between the data and the individual, which is the core purpose of de-identification.
- ✗
Access control
Why it's wrong here
Access control mechanisms, such as role-based access control (RBAC) or discretionary access control (DAC), restrict who can view or manipulate data based on predefined policies and user identities. While crucial for data security and privacy by limiting exposure, these controls do not alter the intrinsic nature or content of the data itself. The data remains fully identifiable to authorized users, thus it is not a de-identification technique.
- ✓
Data masking
Why this is correct
Data masking is a de-identification technique that replaces sensitive, identifiable information with structurally similar but inauthentic data. This process creates a functional but fictitious version of the original data, suitable for purposes like testing, training, or development, without exposing actual personal identifiers. The original data cannot be reconstructed from the masked version, effectively breaking the link to the individual while maintaining data utility.
- ✗
Backup
Why it's wrong here
Backup involves creating copies of data to ensure its availability and recoverability in case of data loss or system failure. This process duplicates the original data, including all its identifiable attributes, without any modification to its content or structure. Therefore, backup is a data availability and disaster recovery strategy, not a method for de-identifying data, as the copies retain the exact same level of identifiability as the source data.
- ✓
Tokenization
Why this is correct
Tokenization is a de-identification method where sensitive data, such as credit card numbers or social security numbers, is replaced with a randomly generated, non-sensitive surrogate value called a token. These tokens bear no mathematical relationship to the original data and cannot be reverse-engineered to reveal the sensitive information. The original sensitive data is securely stored in a separate vault, and only the token is used in less secure environments, effectively removing direct identifiers from processing systems.
Go deeper
Related to this question
Learn chapter
Identity and Access Management (IAM)
Key term
Identification
Identification is the process where a user or device claims an identity, often by providing a username, ID number, or account name, before proving that claim with authentication.
Key term
Data masking
Data masking is a security technique that replaces sensitive data with realistic but fictional data so it can be used safely in non-production environments.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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