DP-300 Implement a secure environment Practice Question
You have an Azure SQL Database that stores sensitive customer data. You need to ensure that the data is encrypted at rest using a customer-managed key stored in Azure Key Vault. What should you configure?
⚠ Common exam trap
Test-takers frequently confuse Always Encrypted (which encrypts specific columns at the client side) with TDE (which encrypts the entire database at rest), and they may choose Always Encrypted because it also uses Azure Key Vault, but it does not meet the 'encryption at rest for the entire database' requirement.
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
✓
Enable Transparent Data Encryption (TDE) with a customer-managed key from Azure Key Vault.
Transparent Data Encryption (TDE) with a customer-managed key stored in Azure Key Vault encrypts the database at rest, using a key that you control and rotate independently. This meets the requirement for encryption at rest with a customer-managed key, as TDE performs real-time I/O encryption and decryption of the data and log files without requiring application changes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Configure dynamic data masking (DDM).
Why it's wrong here
Dynamic data masking obscures column values in query results for non-privileged users, leaving stored data in plaintext and unencrypted. It is correct when you must limit exposure of sensitive values to certain users without altering the underlying storage.
- ✗
Implement row-level security (RLS) to restrict access.
Why it's wrong here
Row-level security filters which rows a user may read or write; it performs no cryptographic operation, so data remains unencrypted at rest. It is the right control when tenants or regions must see only their own rows within a shared table.
- ✓
Enable Transparent Data Encryption (TDE) with a customer-managed key from Azure Key Vault.
Why this is correct
Transparent Data Encryption with a customer-managed key satisfies the encryption-at-rest requirement by wrapping the database encryption key with an asymmetric key held in Azure Key Vault. This gives you control over the key lifecycle, unlike service-managed keys, and TDE operates beneath the application layer, so no schema or query changes are needed.
- ✗
Enable Always Encrypted for the sensitive columns.
Why it's wrong here
Always Encrypted protects column data in use and in transit between client and database, with keys held outside the database engine; it does not satisfy the at-rest TDE requirement using a customer-managed key. It suits protecting specific columns from privileged database administrators.
Go deeper
Related to this question
Learn chapter
Securing Data at Rest and in Transit
Key term
Transparent Data Encryption
Transparent Data Encryption is a security feature that automatically encrypts data written to a database and decrypts it when read, without requiring any changes to the application.
Key term
Azure SQL Performance Tuning
Azure SQL Performance Tuning is the process of optimizing the speed and efficiency of queries and database operations in Microsoft Azure SQL Database or SQL Managed Instance to reduce latency and improve throughput.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DP-300 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DP-300 exam.