What Makes Data Unreadable Without a Key?
Which of the following makes data unreadable without a required key?
Community Insight
The question tests whether you can tell data protection by transformation (encryption) apart from de-identification or access restriction, with the common trap being to pick masking or anonymization because they also 'hide' data.
This DA0-002 practice question asks which technique renders data unreadable unless a required key is supplied, distinguishing encryption from anonymization, masking, and role-based access control. The page establishes that encryption is the only option that mathematically transforms readable plaintext into ciphertext that cannot be reversed without the decryption key.
Test-takers often choose D (Masking) because masking hides data values, but masking replaces or obscures fields for display and does not require a cryptographic key to reverse the transformation.
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Expert Analysis
Why the Answer Is Correct
Encryption converts plaintext into ciphertext using an algorithm and a key, so without the matching key the data is mathematically unreadable — exactly matching the question's wording about a "required key." As jhon456 explained, "A required key is needed to decrypt the data and return it to its original readable form." This is the defining property of encryption and separates it from every other option listed.Why the Other Options Are Wrong
Anonymization (A) removes or alters identifying information so a person cannot be re-identified; it is not reversed with a key and is generally irreversible. Role-based access control (B) governs who may view data at all — it never makes the stored data itself unreadable, so an authorized user still sees clear values. Masking (D) substitutes or obscures values for display or non-production use, but it does not rely on a decryption key to restore the original data.Community Comment Notes
Both rf18 and jhon456 selected C, with jhon456 providing a full breakdown: "Encryption converts readable data (plaintext) into an unreadable form (ciphertext) using an encryption algorithm." rf18 also flagged that "this exam not updated since september 3," which is a reminder to confirm objectives against the current DA0-002 blueprint rather than relying on stale answer keys.Official Reference
Exam Strategy
Anchor on the phrase "required key" — only cryptographic encryption is defined by key-based reversibility. Eliminate options that describe de-identification (anonymization, masking) or permission control (RBAC) before answering.
Frequently Asked Questions
Why is masking not the same as encryption for this question?
Masking hides or substitutes values for display and does not require a cryptographic key to reverse it, so it fails the question's "required key" criterion.
Does role-based access control make stored data unreadable?
No. RBAC only controls who is permitted to access data; the data itself remains in readable form for anyone with the proper role.
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